v0.17.3

In short

• Fixed: a reply or forward made by an assistant without a compose window (a draft, or a direct send) could let
  the end of a quoted message run into the text and signature after it. With Thunderbird's default settings the quote
  was already cleaned up before this point; it mattered mostly with an advanced setting changed by hand. Messages
  written in a compose window were not affected.
• The bridge does not change in this release: nothing to update in your MCP clients if their bridge is 0.17.1.
• No call that worked stops working. Updating is recommended, not urgent.

How to update

• Thunderbird add-on: it updates itself. To get this version now: Add-ons and Themes, gear menu, Check for Updates, then restart Thunderbird. For a first installation, see the README (commonpost-mcp-v0.17.3.xpi below).
• MCP bridge: it is installed in your MCP client and is never updated automatically. This release ships the same bridge as v0.17.1: a bridge of version 0.17.1 needs no update.
  • Claude Desktop: download commonpost-mcp-v0.17.1.mcpb below and open it with Claude Desktop; if the file does not open there (Windows), use Settings > Extensions > Advanced settings > Install Extension.
  • Claude Code with the plugin: /plugin marketplace update commonpost (or turn on auto-update for the marketplace in /plugin), then /reload-plugins. The plugin always carries the bridge of the release.
  • Other clients (Claude Code without the plugin, Cursor, VS Code, ...): download mcp-bridge.cjs below and put it in place of your copy, then restart the client or reconnect the server (/mcp in Claude Code). The path of your copy is in the MCP configuration of the client (Claude Code: claude mcp get <server name>).
  • Not sure which bridges you have? The options page of the add-on (section Bridge) lists the bridges that connected, each with its version and "Up to date", "Newer version available" or "Update recommended". Claude Desktop and another client on the same computer are two bridges, updated separately.

The .sigstore.json files are provenance attestations, not something to install.

All changes

Fixed

• A reply or forward built without a compose window (a draft, or a direct send) could let the end of a quoted message
  run into what follows it: a tag, attribute value, comment or <textarea> left open at the very end of the quote
  took in the caller's text or the signature after it, so markup the quote checks never saw could come out as an
  element. The quote is now replaced by Thunderbird's parsed reading of it, which ends where the quote ends, whenever
  markup put after it would not be read as markup of its own. With Thunderbird's default settings the quote of a
  reply or forward is already parsed before it gets here; messages composed in a window were not affected.

Changed

• The Claude Code plugin manifest lists a terms of service link (the MIT license), for the Claude plugin directory.

v0.17.2

In short

• Fixed: with an identity that writes in HTML, an apostrophe reached the recipient as ' ("j'ai" for
  "j'ai") in a draft, a direct send, or a reply or forward made by an assistant without a compose window. Non-breaking
  spaces and other special characters of an HTML body, an HTML signature or a quoted message showed the same way.
  Messages written in a compose window were not affected.
• The bridge does not change in this release: nothing to update in your MCP clients if their bridge is 0.17.1.
• No call that worked stops working. Updating is recommended, not urgent.

How to update

• Thunderbird add-on: it updates itself. To get this version now: Add-ons and Themes, gear menu, Check for Updates, then restart Thunderbird. For a first installation, see the README (commonpost-mcp-v0.17.2.xpi below).
• MCP bridge: it is installed in your MCP client and is never updated automatically. This release ships the same bridge as v0.17.1: a bridge of version 0.17.1 needs no update.
  • Claude Desktop: download commonpost-mcp-v0.17.1.mcpb below and open it with Claude Desktop; if the file does not open there (Windows), use Settings > Extensions > Advanced settings > Install Extension.
  • Claude Code with the plugin: /plugin marketplace update commonpost (or turn on auto-update for the marketplace in /plugin), then /reload-plugins. The plugin always carries the bridge of the release.
  • Other clients (Claude Code without the plugin, Cursor, VS Code, ...): download mcp-bridge.cjs below and put it in place of your copy, then restart the client or reconnect the server (/mcp in Claude Code). The path of your copy is in the MCP configuration of the client (Claude Code: claude mcp get <server name>).
  • Not sure which bridges you have? The options page of the add-on (section Bridge) lists the bridges that connected, each with its version and "Up to date", "Newer version available" or "Update recommended". Claude Desktop and another client on the same computer are two bridges, updated separately.

The .sigstore.json files are provenance attestations, not something to install.

All changes

Fixed

• An apostrophe reached the recipient as ' (j'ai for "j'ai") in an HTML message built without a compose
  window: saveDraft, a direct sendMail, and the text of a reply or forward sent directly or saved as a draft, when
  the identity composes in HTML. The same happened to any character reference in an HTML body (',  ,
  é...), and in an HTML signature or quoted message that has one. Thunderbird's send path escapes the & of
  every reference but <, >, & and ", which are the only ones its editor writes; these bodies
  now reach it with the other references decoded, as the editor would have written them. A body in which this would
  change more than the text (an HTML body with a > inside a quoted attribute value) goes as before. Messages composed
  in a window were not affected.

v0.17.1

In short

Security release: update both the add-on and the bridge. Files of a Thunderbird profile, or of an account's local
mail folder, kept outside the default locations could be attached to a message; they are now refused. A bridge
older than 0.17.1 does not apply this check: the add-on now recommends updating it (Claude Code plugin: update the
plugin; Claude Desktop: install the new .mcpb; elsewhere: replace mcp-bridge.cjs). No call that worked stops
working, except attaching files from those folders.

How to update

• Thunderbird add-on: it updates itself. To get this version now: Add-ons and Themes, gear menu, Check for Updates, then restart Thunderbird. For a first installation, see the README (commonpost-mcp-v0.17.1.xpi below).
• MCP bridge: it is installed in your MCP client and is never updated automatically. This release changes the bridge: update it in every MCP client that uses it.
  • Claude Desktop: download commonpost-mcp-v0.17.1.mcpb below and open it with Claude Desktop; if the file does not open there (Windows), use Settings > Extensions > Advanced settings > Install Extension.
  • Claude Code with the plugin: /plugin marketplace update commonpost (or turn on auto-update for the marketplace in /plugin), then /reload-plugins. The plugin always carries the bridge of the release.
  • Other clients (Claude Code without the plugin, Cursor, VS Code, ...): download mcp-bridge.cjs below and put it in place of your copy, then restart the client or reconnect the server (/mcp in Claude Code). The path of your copy is in the MCP configuration of the client (Claude Code: claude mcp get <server name>).
  • Not sure which bridges you have? The options page of the add-on (section Bridge) lists the bridges that connected, each with its version and "Up to date", "Newer version available" or "Update recommended". Claude Desktop and another client on the same computer are two bridges, updated separately.

The .sigstore.json files are provenance attestations, not something to install.

All changes

Security

• Attachments: the add-on lists the folders of the running Thunderbird profile, of every other profile Thunderbird
  knows and of every account's local mail folder, wherever they are, in the connection file; the bridge refuses a
  path attachment under any of them (by the path given, its real path, and the folder's identity, so a link or a
  second mount of the same folder is refused too). The bridge now finds Thunderbird before it accepts a path
  attachment, and checks again if a request ends up going to another Thunderbird than the one it was checked
  against. The add-on applies a similar check, by path and real path, to path attachments it receives directly. Not covered: the account
  folders of profiles other than the running one, a mail store at the root of a drive, and a folder the bridge
  sees under another path (a bridge under WSL or in a container). See "Attachments refused" in the README.

Changed

• Bridge 0.17.1. The add-on recommends it (MIN_BRIDGE_VERSION 0.17.1); older bridges keep working.
• The connection file is written in ASCII (non-ASCII characters escaped), so a path with accents reads back the same.

v0.17.0

In short

• New: a Claude Code plugin. Add this repository as a plugin marketplace (claude plugin marketplace add commonpost/thunderbird-mcp, or "Add marketplace" in Customize > Plugins of your Claude account) and install
  commonpost-mcp: the plugin carries the bridge of the release, so there is no mcp-bridge.cjs to download or to
  replace by hand, and updating the plugin updates the bridge. It works in Claude Code and Cowork; the chat of
  Claude Desktop still needs the .mcpb bundle.
• The bridge does not change in this release: nothing to update in your MCP clients if their bridge is 0.14.0. A
  bridge 0.13 keeps working; updating it is optional.
• No call that worked stops working. Updating is not urgent.

How to update

• Thunderbird add-on: it updates itself. To get this version now: Add-ons and Themes, gear menu, Check for Updates, then restart Thunderbird. For a first installation, see the README (commonpost-mcp-v0.17.0.xpi below).
• MCP bridge: it is installed in your MCP client and is never updated automatically. This release ships the same bridge as v0.14.0: a bridge of version 0.14.0 needs no update.
  • Claude Desktop: download commonpost-mcp-v0.14.0.mcpb below and open it with Claude Desktop; if the file does not open there (Windows), use Settings > Extensions > Advanced settings > Install Extension.
  • Claude Code with the plugin: /plugin marketplace update commonpost (or turn on auto-update for the marketplace in /plugin), then /reload-plugins. The plugin always carries the bridge of the release.
  • Other clients (Claude Code without the plugin, Cursor, VS Code, ...): download mcp-bridge.cjs below and put it in place of your copy, then restart the client or reconnect the server (/mcp in Claude Code). The path of your copy is in the MCP configuration of the client (Claude Code: claude mcp get <server name>).
  • Not sure which bridges you have? The options page of the add-on (section Bridge) lists the bridges that connected, each with its version and "Up to date", "Newer version available" or "Update recommended". Claude Desktop and another client on the same computer are two bridges, updated separately.

The .sigstore.json files are provenance attestations, not something to install.

All changes

Added

• A Claude Code plugin: this repository is a plugin marketplace (claude plugin marketplace add commonpost/thunderbird-mcp, then claude plugin install commonpost-mcp@commonpost). The plugin
  (plugins/claude-code/) declares the commonpost-mail server and carries the bridge of the release, so Claude Code
  users have no mcp-bridge.cjs to download or to replace by hand: updating the plugin updates the bridge. Its version
  is the product's and its bridge a byte-for-byte copy of the repository's (the version check requires both), so every
  release reaches plugin users.
  The plugin folder carries its own README, LICENSE and listing icon, as Anthropic's plugin directory requires.

v0.16.0

In short

• Fixed: listEvents lists a whole day when it is asked for one date (2026-10-15 to 2026-10-15): it returned
  nothing, with no error, so an assistant answered that the day was free. A date without a time is now a day in
  local time.
• Fixed: a folder address written with a trailing slash is accepted; createFolder answered "Folder not found".
• Changed: three answers now tell an assistant what it needs to go on: an empty search of several words says
  why it found nothing, a draft whose recipient has no e-mail address carries a warning, and renameFolder returns
  the new address of the folder.
• The bridge does not change in this release: nothing to update in your MCP clients if their bridge is 0.14.0. A
  bridge 0.13 keeps working; updating it is optional.
• No call that worked stops working. Updating is not urgent.

How to update

• Thunderbird add-on: it updates itself. To get this version now: Add-ons and Themes, gear menu, Check for Updates, then restart Thunderbird. For a first installation, see the README (commonpost-mcp-v0.16.0.xpi below).
• MCP bridge: it is installed in your MCP client and is never updated automatically. This release ships the same bridge as v0.14.0: a bridge of version 0.14.0 needs no update.
  • Claude Desktop: download commonpost-mcp-v0.14.0.mcpb below and open it with Claude Desktop; if the file does not open there (Windows), use Settings > Extensions > Advanced settings > Install Extension.
  • Other clients (Claude Code, Cursor, VS Code, ...): download mcp-bridge.cjs below and put it in place of your copy, then restart the client or reconnect the server (/mcp in Claude Code). The path of your copy is in the MCP configuration of the client (Claude Code: claude mcp get <server name>).
  • Not sure which bridges you have? The options page of the add-on (section Bridge) lists the bridges that connected, each with its version and "Up to date", "Newer version available" or "Update recommended". Claude Desktop and another client on the same computer are two bridges, updated separately.

The .sigstore.json files are provenance attestations, not something to install.

All changes

Changed

• searchMessages adds a hint to an empty result of a search of several words: every word must match as written,
  and a single leading operator (from:Carol training budget) sends every word to that field. Results that found
  something are unchanged.
• sendMail, saveDraft, replyToMessage and forwardMessage add a warning when a recipient has no e-mail address
  (to: "Frank Osei"): the draft was saved and reported as a success, addressed to nobody. The call still succeeds,
  because the name of a Thunderbird mailing list is such a recipient too. A direct send that fails names it as the
  likely cause.
• renameFolder returns the new URI of the folder as path, next to oldPath, and says so in its message: a caller
  that went on with the old URI got "Folder not found".

Fixed

• listEvents lists a whole day when startDate and endDate are the same date without a time (2026-10-15): it
  returned an empty list, with no error, and an assistant answered that the day was free. A date without a time is now
  a calendar day in local time: as startDate the start of that day, as endDate the end of it. A date with a time
  is read as before.
• A folder URI written with a trailing slash (mailbox://nobody@Local%20Folders/) is accepted wherever a tool takes
  a folder: createFolder answered "Folder not found" for it. moveFolder still says "already under this parent"
  when that parent is written this way.
• Release pages name the .mcpb file as it is published. The bundle carries the version of the bridge, so a release
  that does not change the bridge ships the bundle of an earlier version: the page of 0.15.0 said
  commonpost-mcp-v0.15.0.mcpb for the file commonpost-mcp-v0.14.0.mcpb (corrected by hand on that page).

v0.15.0

In short

• New: saved searches (virtual folders): create one with createFolder, list them with listFolders, delete one
  with deleteFolder. A saved search is a live view: nothing is moved, copied or deleted.
• New: Thunderbird shows a notification when an MCP client connects with a bridge that should be updated, and
  the options page (section Bridge) now says "Newer version available" for a bridge that works but is not the latest.
• Changed: release pages say whether updating the bridge is needed or optional.
• The bridge does not change in this release: nothing to update in your MCP clients if their bridge is 0.14.0. A
  bridge 0.13 keeps working; updating it is optional.
• No call that worked stops working.

How to update

• Thunderbird add-on: it updates itself. To get this version now: Add-ons and Themes, gear menu, Check for Updates, then restart Thunderbird. For a first installation, see the README (commonpost-mcp-v0.15.0.xpi below).
• MCP bridge: it is installed in your MCP client and is never updated automatically. This release ships the same bridge as v0.14.0: a bridge of version 0.14.0 needs no update.
  • Claude Desktop: download commonpost-mcp-v0.14.0.mcpb below and open it with Claude Desktop; if the file does not open there (Windows), use Settings > Extensions > Advanced settings > Install Extension.
  • Other clients (Claude Code, Cursor, VS Code, ...): download mcp-bridge.cjs below and put it in place of your copy, then restart the client or reconnect the server (/mcp in Claude Code). The path of your copy is in the MCP configuration of the client (Claude Code: claude mcp get <server name>).
  • Not sure which bridges you have? The options page of the add-on (section Bridge) lists the bridges that connected, each with its version and "Up to date", "Newer version available" or "Update recommended". Claude Desktop and another client on the same computer are two bridges, updated separately.

The .sigstore.json files are provenance attestations, not something to install.

All changes

Added

• A system notification when a bridge that the add-on recommends updating, or refuses, connects: once per bridge and
  per Thunderbird session. The hidden preference extensions.commonpost-mcp.bridgeUpdateAlert (false) turns it off.
  It uses the notifications of the system; on a Linux desktop without a notification service nothing is shown.
• The options page (section Bridge) shows "Newer version available" for a bridge that works but is not the one
  published with the add-on, and names that version.
• Saved searches (virtual folders), through createFolder (savedSearch), listFolders (savedSearches) and
  deleteFolder (a saved search is deleted as a view, never as mail). By Sven Scharmentke (@svnscha), from
  TKasperczyk/thunderbird-mcp#198. Conditions are the same as createFilter's (same typed values and address-book
  restrictions), at most 50 folders and 50 conditions; a searched folder of an excluded account is counted in
  hiddenSearchFolders, never named.

Changed

• The release page calls the bridge update optional when the oldest recommended bridge does not change.

v0.14.0

In short

• Security: with 0.13.0, a reply or a forward saved as a draft (mode: "draft") could carry an image or a link
  of the original message that Thunderbird fetches and attaches when the draft is opened and sent. Fixed here; update
  if you use drafts of replies or forwards. Direct sends and replies made in Thunderbird's window were not affected.
• New: replyToMessage can answer the newest message of a conversation (latestInThread), in a window or as a
  draft.
• Fixed: a signature with images read from files, and the bridge now waits long enough for a slow send or save.
• Changes you may notice: moz-do-not-send="false" in an HTML body passed to the compose tools is no longer
  kept. No call that worked stops working.
• This release changes the bridge: update it in every MCP client (steps below). A bridge 0.13 keeps working.

How to update

• Thunderbird add-on: it updates itself. To get this version now: Add-ons and Themes, gear menu, Check for Updates, then restart Thunderbird. For a first installation, see the README (commonpost-mcp-v0.14.0.xpi below).
• MCP bridge: it is installed in your MCP client and is never updated automatically. This release changes the bridge: update it in every MCP client that uses it.
  • Claude Desktop: download commonpost-mcp-v0.14.0.mcpb below and open it with Claude Desktop; if the file does not open there (Windows), use Settings > Extensions > Advanced settings > Install Extension.
  • Other clients (Claude Code, Cursor, VS Code, ...): download mcp-bridge.cjs below and put it in place of your copy, then restart the client or reconnect the server (/mcp in Claude Code). The path of your copy is in the MCP configuration of the client (Claude Code: claude mcp get <server name>).
  • Not sure which bridges you have? The options page of the add-on (section Bridge) lists the bridges that connected, each with its version and "Up to date" or "Update recommended". Claude Desktop and another client on the same computer are two bridges, updated separately.

The .sigstore.json files are provenance attestations, not something to install.

All changes

Added

• replyToMessage latestInThread: true replies to the newest message of the conversation (Sent included; Drafts,
  Templates and the Outbox left out), found as searchMessages threadOf finds it. When that is another message
  than the one passed, the result names it in repliedTo (messageId, folderPath, date, and
  linkedBy: "subject" when it has no References to the conversation). The server instructions gain a line on
  replies and one on editing drafts with saveDraft draftId. Thanks to Konstantin (@mazixs), last piece of #18.
  • Only for a window or a draft, which you review: with mode: "send" (or skipReview) it is refused, because
    anyone can join a conversation with a message and the newest one would be quoted and answered unseen. It also
    needs the searchMessages tool enabled.
  • threadIncomplete: true in the result means the mailbox holds more messages than the conversation search reads
    (10,000 headers): a newer message may exist.

Security

• A reply or a forward saved as a draft (mode: "draft") could keep an image or a link of the original message
  without the moz-do-not-send="true" mark that Thunderbird's own reply sets, and with the sender's own
  moz-do-not-send="false". The mark was set on the tags found in the text of the quote, and a tag that the text
  and Thunderbird's parser read differently (a quote character in an attribute name is enough) was missed. Opened in
  the compose window and sent, such a draft makes Thunderbird fetch the URL and attach what it gets, as it does for
  an object marked "false". The elements Thunderbird's parser finds in the quote are now checked after the text,
  and no moz-do-not-send written by the message is kept. A direct send was not affected (it embeds nothing), nor
  a reply made in Thunderbird's window.
• The <html>, <head> and <body> tags of a quoted message are removed from its text; a <body> tag could be
  left when the removal itself put one together (<bo<body x>dy background=...>), and it then gave its attributes,
  a background image for one, to the body of the draft. What is left of such a tag is now text.
• moz-do-not-send="false" in the HTML body given by the caller (sendMail, saveDraft, replyToMessage,
  forwardMessage) is no longer kept either, for the same reason: text an assistant wrote after reading a message
  must not make Thunderbird fetch and attach a URL. moz-do-not-send="true" is kept.

Fixed

• A signature with file:// images: the URL that was replaced by its data was looked for in a lower-cased copy of the
  signature, made again for every URL, and a character whose lower case is longer (U+0130) before a URL moved the
  place that was replaced. The signature is now read once, as it is.
• mcp-bridge.cjs waits up to 180 s, instead of 150 s, for a direct send or a saved draft. Before the 120 s of the
  send or the save, the add-on can wait for a folder summary (20 s), the original message (20 s) and its quote
  (15 s): 175 s in all, so a bridge that gave up at 150 s could report a failure for a message that still went out. A
  test now keeps the wait of the bridge above the sum of the waits of the add-on. A bridge 0.13 keeps working.

v0.13.0

In short

• New: saveDraft can edit an existing draft (draftId) instead of creating another one. A reply or a forward
  saved as a draft or sent directly, and a new draft, now have the body Thunderbird itself would write: the quote with
  its formatting, the forward header, your signature.
• Fixed: the bridge waits long enough for saveDraft: a slow save could be reported as failed and end in a second
  draft. The notice about a bridge to update no longer skips a session that starts shortly after another one, and
  says where the bridge is.
• Changes you may notice: drafts and direct sends now carry your signature when you have one, and the subject of
  a forward made without a window always gets the Fwd: prefix. No call that worked stops working.
• This release changes the bridge: update it in every MCP client (steps below). A bridge 0.12 keeps working, and
  the add-on reminds you until it is replaced.
• Release pages start with this summary and the steps to update, from now on.

How to update

• Thunderbird add-on: it updates itself. To get this version now: Add-ons and Themes, gear menu, Check for Updates, then restart Thunderbird. For a first installation, see the README (commonpost-mcp-v0.13.0.xpi below).
• MCP bridge: it is installed in your MCP client and is never updated automatically. This release changes the bridge: update it in every MCP client that uses it.
  • Claude Desktop: download commonpost-mcp-v0.13.0.mcpb below and open it with Claude Desktop; if the file does not open there (Windows), use Settings > Extensions > Advanced settings > Install Extension.
  • Other clients (Claude Code, Cursor, VS Code, ...): download mcp-bridge.cjs below and put it in place of your copy, then restart the client or reconnect the server (/mcp in Claude Code). The path of your copy is in the MCP configuration of the client (Claude Code: claude mcp get <server name>).
  • Not sure which bridges you have? The options page of the add-on (section Bridge) lists the bridges that connected, each with its version and "Up to date" or "Update recommended". Claude Desktop and another client on the same computer are two bridges, updated separately.

The .sigstore.json files are provenance attestations, not something to install.

All changes

Added

• Every release page now starts with a summary in plain words ("In short": what is new, what is fixed, what breaks),
  then the steps to update the add-on and the bridge, with a line that says whether the release changes the bridge,
  then the list of changes as before. scripts/release-notes.cjs writes it from CHANGELOG.md and BRIDGE_VERSION;
  from 0.13.0 on, a release whose CHANGELOG section has no summary is refused by the Version sync check.
• saveDraft takes draftId (and optionally its folderPath) to edit an existing draft instead of deleting and
  recreating it, as Thunderbird does when a draft is reopened and saved. Passed fields replace, the others are kept:
  recipients, subject, body, attachments, Reply-To, priority, References, Content-Language, the return receipt / DSN /
  delivery format flags and the reply or forward state. The draft keeps the format of its body; isHtml changes it only
  when the whole body is replaced. The old version is removed once the new one is stored. The result has the new
  messageId (Thunderbird gives every saved draft a new one) and replacedDraftId. With a new body, keepQuote
  (default true) replaces only the typed text and keeps the cite line, quote, forwarded message and signature;
  keepAttachments: false drops the draft's attachments. By @mazixs in #30.
  A refused attachment fails the whole call, as for a new draft, and an encrypted draft is not rewritten while
  encrypted content is not allowed: in both cases the draft stays as it is.

Changed

• The add-on recommends bridge 0.13.0 or newer (MIN_BRIDGE_VERSION), the first that waits 150 s for saveDraft:
  an older bridge still works, and gets the notice to update in a tool result and "Update recommended" in the
  options page. mode: "send" and "draft" keep their own minimum, 0.12.0.
• The notice for a bridge to update, in a tool result and in the options page (section Bridge), says where the copy
  to replace is (the MCP configuration of the client; claude mcp get <server name> in Claude Code) and how to
  install the .mcpb bundle when the file does not open in Claude Desktop (Settings > Extensions > Advanced settings

  Install Extension). The options page and the README say that each MCP client has its own bridge.

• A reply without a window (mode: "draft" or "send"), saveDraft and sendMail with skipReview get the body
  Thunderbird's compose window would save with the same text typed at its caret: the localized cite line
  (mailnews.reply_header_type), the quote from Thunderbird's own quoting (nsIMsgQuote) with the original's HTML
  formatting, the identity's signature (text, HTML, file or image) placed by its reply position and signature
  settings, HTML in UTF-8, plain text as format=flowed wrapped at mailnews.wraplength. Before, a reply quoted the
  plain-text body by hand under an English "On ..., ... wrote:" line without a signature, a new message got no
  signature, a plain body went out labeled format=flowed without being flowed, and an HTML body (isHtml: true)
  had every non-ASCII character written as a &#...; reference, which made a Cyrillic body several times larger. By
  @mazixs in #28.
  While encrypted content is not allowed, Thunderbird's own quote, which decrypts, is taken only for a message that
  was read and holds no encrypted part: a reply to a message that could not be read in time quotes nothing, as before.
• A forward without a window (mode: "draft" or "send") gets the body Thunderbird's forward window would save with
  the same text typed at its caret: the localized forward header (mail.show_headers), the forwarded body with the
  original's HTML formatting, and the identity's signature placed by its forward and position settings. Before, a
  forward quoted the plain-text body by hand under an English "Forwarded Message" header without a signature. By
  @mazixs in #29.
  • A plain-text forward keeps the signature below the forwarded message, as Thunderbird 140 and 158+ do.
    Thunderbird 150-157 drop it (bug 2063939, a regression from Gecko bug 2019689); the tool does not copy that bug.
• The subject of a forward without a window is mail.forward_subject_prefix (default Fwd) and the original's
  subject as the message database keeps it, as Thunderbird's forward makes it: a forward of "Re: x" is "Fwd: x", and
  of "Fwd: x" is "Fwd: Fwd: x". Before, the prefix was always Fwd and was not added to a subject that had it. By
  @mazixs in #29.

Fixed

• mcp-bridge.cjs: a saveDraft call waits up to 150 s for Thunderbird, like replyToMessage and forwardMessage
  with mode: "draft", instead of 30 s. Thunderbird can take up to 120 s to save a draft, so the bridge used to
  report a timeout for a draft that was still being saved, and a client that retried would create two. After that
  wait the error says the draft may still appear in the Drafts folder later.
• The notice for a bridge to update reached only one of several clients that share an entry, as every bridge 0.11
  or older does (it sends no version): a session that listed its tools within 10 minutes of that notice never got
  one. Its notice now waits and goes out with its first tool call after those 10 minutes.

v0.12.0

Breaking

• replyToMessage with skipReview now needs explicit to and from, and forwardMessage with skipReview an
  explicit from. A direct send no longer takes any address from the original message, which anyone can write: it
  goes only to the caller's to / cc / bcc plus the sending identity's own automatic Cc / Bcc, with that
  identity's Reply-To (a direct reply-all no longer adds the original's To / Cc). The result of a direct send lists
  the from, to, cc, bcc and replyTo it went out with. By @mazixs in #26.
• The error that replyToMessage and forwardMessage return when direct sending is blocked has new text, and it now
  covers mode: "send" as well as skipReview: it was "User preference blocks skipReview. Retry with skipReview:
  false (or omitted) to open the review window instead.", it is now "User preference blocks direct sending (mode
  "send" or skipReview). Use mode "draft" to save a draft, or "window" (the default) to open a review
  window." A client that matches the old string exactly must be updated (sendMail, createEvent and createTask
  keep theirs). By @mazixs in #27.

Added

• replyToMessage and forwardMessage take mode: window (the default, the review window as before), draft or
  send. mode: "send" is a direct send, the same as skipReview: true, with the same rules: explicit to and
  from, subject to Block skipReview, and the bridge waits up to 150 s for it. mode: "draft" saves the
  reply or forward to the identity's Drafts folder without opening a window and returns its messageId and
  folderPath. It sends nothing, so Block skipReview does not block it. By @mazixs in #27.
  mode: "draft" needs the saveDraft tool to be enabled: a tool the user disabled is not reachable through
  another tool, and the call returns an error saying so.
  • A reply draft gets the recipients Thunderbird's Reply / Reply All computes (nsMsgCompose.cpp, ported to a
    pure function): Reply-To and Mail-Reply-To, Mail-Followup-To for Reply All, the author instead of a mailing list
    that rewrites Reply-To, the recipients of your own message from the identity that sent it, your own addresses
    dropped, and the identity's automatic Cc / Bcc and Reply-To. A to or cc from the caller replaces the
    computed one.
  • The draft stores the state Thunderbird's own reply or forward draft stores (origURIs, queuedDisposition), so
    the original is marked as replied or forwarded when the draft is sent, not when it is saved.
  • The body is quoted by the tool, as for a direct send.
• The bridge tells the user, once per connection, when the add-on is older than the version it needs
  (MIN_EXTENSION_VERSION, 0.12.0). After the first tools/list or tools/call that Thunderbird answers, it sends
  the add-on an initialize on the same validated connection (1.5 s at most, answer capped at 64 KB) and, if the
  add-on is older, appends one text item to the result of the next tools/call (Check for Updates, then restart
  Thunderbird; the release page) and writes one line to stderr. Never for a direct send (skipReview or
  mode: "send"); silent when a version is missing, 0.0.0 or malformed, or when the server is not commonpost-mcp; only
  digits from the add-on reach the text. When the add-on is newer, the add-on judges the bridge (below).
• A .mcpb bundle for Claude Desktop (macOS and Windows), attached to each release from the next one on: commonpost-mcp-v<version>.mcpb, with a provenance attestation. It contains only the stdio bridge (mcp-bridge.cjs, LICENSE, THIRD-PARTY.md, an icon and a manifest.json in mcpb/, manifest_version 0.3), needs Node.js 22 or later and the add-on of the same release or newer, has no settings and is not signed. It is built by scripts/build-mcpb-reproducible.cjs like the XPI (committed files only, sorted stored entries, fixed date: the same bytes on any Node version), and the release job rebuilds it from the tag and refuses any difference. The zip writer moved to scripts/zip-stored.cjs (the XPI is byte for byte unchanged). The Version sync check and the tag check now cover mcpb/manifest.json too.
• The bridge ignores COMMONPOST_MCP_CONNECTION_FILE when its value is exactly an unexpanded ${user_config.…} placeholder (a client passing an empty optional field through as text) and runs the automatic discovery, instead of pinning itself to a path that cannot exist.
• The bridge answers server/discover itself, at once, with the JSON-RPC error -32601 "Method not found", without
  contacting Thunderbird. Clients that speak both protocol eras (MCP 2026-07-28 and earlier, such as Claude Desktop)
  probe with it first and fall back to initialize; the probe used to reach Thunderbird and, with Thunderbird closed,
  came back after about 5 s with a discovery error that named local paths.
• The bridge announces itself on every request to the add-on, in the X-Commonpost-Bridge header: its version, how it
  was installed (packaging=mcpb when the .mcpb bundle sets COMMONPOST_MCP_PACKAGING=mcpb, otherwise file) and,
  when COMMONPOST_MCP_PROFILE holds a valid name (a-z, 0-9 and -, 32 at most), profile=<name>, reserved for
  per-client tool sets (nothing uses it yet). The header is self-declared: it is not a security boundary, the token
  is.
• The add-on judges bridges older than itself: once per client session (at most every 10 minutes) it adds a notice to
  a tool result when the bridge is older than 0.12.0 or reports no version (0.11 or older), with the release page and
  what to do (.mcpb or file); never on a direct send. It refuses replyToMessage / forwardMessage with
  mode: "send" or "draft" (without skipReview) from such a bridge before doing anything, because an old bridge stops
  waiting after 30 s and can report a failure for a message that is still being sent; mode: "window" and every other
  call keep working. A program that calls the HTTP API directly can declare itself with the header (README,
  Development).
• A local security floor in the add-on (BRIDGE_SECURITY_FLOOR), shipped disarmed (0.0.0): if a future release arms
  it, every tool call from an older bridge, or from a client without the header, is refused before anything acts, with
  the reason and the release page; tools/list keeps answering. No remote switch, no setting to bypass it.
• Options page, section "Bridge": the bridges that connected since Thunderbird started (version, installation,
  profile, last seen, status) and the release page to update one. Kept in memory only.

Changed

• Without from, replyToMessage and forwardMessage use the identity Thunderbird's own Reply / Forward picks
  (MailUtils.getIdentityForHeader, as ComposeMessage in mailCommands.js calls it) instead of the account's
  default identity: the identity the message was addressed to (To / Cc, then Delivered-To), the identity that sent
  it for a reply to your own message, and for a catch-all identity the address the message was sent to. Identities
  of accounts the MCP may not access are never picked. By @mazixs in #26.
  An identity shared by an accessible and a restricted account counts as accessible, whatever the order of the
  accounts, as findIdentity already did. Fetching the original message for that choice gives up after 20 s: a
  compose window or a draft then opens without it, and a direct send returns an error instead of hanging. Encrypted
  messages stay withheld from a direct reply or forward while the "read encrypted messages" option is off.
• saveDraft saves through nsIMsgCompose, as Thunderbird's compose window does, and returns the new draft's
  messageId and folderPath. If nsIMsgCompose cannot be used, it falls back to the previous nsIMsgSend path.
  By @mazixs in #27.
• forwardMessage no longer requires to, except with mode: "send" (or skipReview). By @mazixs in #27.
• A reply's References header is the original's References plus its Message-ID, as Thunderbird's reply builds it
  (it used to be the original's Message-ID only); Thunderbird trims a chain longer than the header limit when it
  writes the message, as for its own reply. A reply to a message without Message-ID gets no References. In-Reply-To
  is no longer set by the tool: Thunderbird derives it from the last References entry. By @mazixs in #27.
• mcp-bridge.cjs: a replyToMessage or forwardMessage call with mode: "send" is a direct send like
  skipReview: true, so it waits up to 150 s and gets the same "outcome unknown" error on a timeout. By @mazixs in
  #27. On top, from the maintainers: the mode is compared trimmed and lower-cased to decide that (so "SEND", which
  the extension refuses, still counts as a send: no version notice, the long wait), without changing what is sent to
  the extension; and mode: "draft" waits 150 s too, since Thunderbird can take up to 120 s to save a draft and a
  client that retries after 30 s would create two. After that wait the error says the draft may still appear in the
  Drafts folder later.
• README: a "Quick install" section at the top, in five steps, with the Claude Code command (Windows example included) and a bold reminder that the bridge is not updated with the extension. It also corrects the old advice to replace the bridge's package.json too: the release ships only mcp-bridge.cjs, which needs nothing else.
• README: a new "Other MCP clients" section with the configuration file, location and format of Claude Desktop, VS Code, Cursor, OpenAI Codex CLI and Gemini CLI, checked against each client's documentation, and when and how to set COMMONPOST_MCP_CONNECTION_FILE (only if the bridge cannot find the connection file). The bridge is not tied to any client, and mcpServers is not the key every client uses.
• RELEASING: the verification step now says that a rebase merge rewrites the commit date, so the ...

v0.11.0

The MCP protocol changes below come from #16 by Konstantin (mazixs), rebased on 0.10.1. Its own removal of
invisible characters was replaced by 0.10.0's handling of untrusted content, which covers the same ground; the
escaping of what is left, the table and dupLocations handling and the disabled-tool wording were added on top.

The search and reading changes come from #17 by Konstantin (mazixs), rebased on top of #16. On top of it, the
maintainers keep encrypted messages withheld in its new outputs, apply the account restriction to its new paths,
treat its new identifiers and the decoded rawSource like the rest of 0.10.0's untrusted-content handling, find
addresses in headers in linear time (two of its regular expressions backtracked quadratically on a long header a
sender can write), and applied the review of #17.

Breaking

• getFilterConfirmation is removed, which brings the server back to 40 tools, the limit Cursor accepts per MCP
  server. Call listFilters with confirmation: true instead: it returns the same read-only view (the pending
  request and the recent ones, with the limits) and ignores accountId; adding confirmationId reads one
  request, as before (an unknown id is the same error). confirmationId is ignored without confirmation: true.
  Without confirmation, listFilters is unchanged. A disabled-tools preference that still names getFilterConfirmation is harmless. Disabling
  listFilters now also disables the confirmation view.

• Tool failures are tool results with isError: true and { "error": "..." } instead of JSON-RPC errors, as the
  MCP spec asks for errors the model can act on: invalid arguments, a disabled tool, a handler that throws or
  returns { error } (including a message-tool result too large to check for untrusted content, which is still
  refused as a whole), an attachment path the bridge refuses, Thunderbird not reachable, a timeout (with a note
  that the operation may still complete, except for a direct send, whose error already says that the outcome is
  unknown). JSON-RPC errors remain for protocol problems only, with new codes: unknown tool or missing name
  -32602, internal errors -32603 (the extension used -32000), unparsable input -32700 (the bridge used
  -32700 for every failure).

• Values outside their bounds are rejected with an error that names the bound: priority 0-9 (createTask,
  updateTask), percentComplete 0-100 (updateTask clamped 150 to 100 before). Only limits are clamped:
  maxResults of listEvents / listTasks is an integer from 1 to 500, a larger value becomes 500 and a fraction
  is floored, while 0 is an error (it meant the default of 100 before).

• createEvent.status is an enum (tentative, confirmed, cancelled, in any case); an empty string, which
  meant the default, is rejected, so omit the parameter instead. updateEvent.status stays a free string on
  purpose: an empty string there removes the event's status, and any other value is still checked against the
  same three values, in any case.

• searchMessages and getRecentMessages return a new envelope and compact rows, for every client (#17).
  format: "legacy" returns the old envelope and rows: it is deprecated and will be removed in a later release,
  keeps the new folder default (pass includeTrash: true for the old one) and the decoded ccList, and cannot be
  combined with groupBy.

  	0.10.x	now
  Result	a plain array; { messages, totalMatches, offset, limit, hasMore } only when offset is passed	always { messages, totalMatches, offset, limit, hasMore }, plus incomplete: true when the scan stopped at 10,000 matches
  Default rows	50 (max 200)	20 (max 200); format: "legacy" keeps 50
  Folders	every folder, Trash and Junk included	Trash and Junk skipped unless includeTrash: true or an explicit folderPath
  threadId, folder	present	omitted (threadId is folder-local; folderPath identifies the folder)
  Empty fields, flagged: false	present ("", [], false)	omitted
  preview	the whole stored preview	the first 120 characters, then ...
  subject of a reply	without Re:, as stored in the database	with Re:, as Thunderbird displays it
  ccList	as stored (may hold MIME encoded-words)	decoded

• getMessage / getMessages cut long bodies by default: 20,000 characters for getMessage and 4,000 per message
  for getMessages (maxBodyChars, up to 200,000). A longer body sets bodyTruncated, nextBodyOffset and
  bodyTotalChars; getMessage reads the rest with bodyOffset. The same cap applies to rawSource (#17).

• rawSource is decoded text instead of a Latin-1 byte string (see Added), and hidden characters are removed from
  it and counted, as in a body. rawEncoding: "base64" returns the exact bytes (#17).

• getMessage: the subject of a reply keeps Re: as Thunderbird displays it (the database stores it without),
  and ccList is decoded, also in the result of an encrypted message. The subject of an encrypted message and of
  rawSource stays the wire-level one, as in 0.10.0; displayMessage is unchanged (#17).

• Search parameters are checked like the others (#17): offset must be a whole number from 0, daysBack a whole
  number from 1 (0 meant the default of 7, and fractions were floored), bodyOffset a whole number from 0, and
  sortOrder asc or desc; other values are errors. maxResults of searchMessages, getRecentMessages and
  searchContacts is an integer from 1 to 200 and maxBodyChars one from 1 to 200,000: a larger value becomes the
  maximum and a fraction is floored, while 0 is an error (for maxResults it meant the default before).

• searchContacts leaves empty fields out of each contact and also matches the organization (#17).

Added

• initialize returns short server instructions (IDs, untrusted mail content, search, review windows, stale
  IMAP folders), identical in the bridge and the extension. The three lines on search (counts, tables, body
  paging, company mail, conversations) come with #17.
• tools/list entries carry title and all four annotations (readOnlyHint, destructiveHint, idempotentHint,
  openWorldHint) set explicitly, since the spec defaults assume a destructive open-world tool. They err on the
  cautious side: sendMail, replyToMessage, forwardMessage, createFilter, updateFilter and applyFilters
  are destructive and open-world (a sent message can't be taken back, and filter rules can forward or reply), and
  getMessage / getMessages (saveAttachments writes files) and displayMessage (a displayed message is marked
  read) are not read-only.
• searchMessages: participant: matches From, To, Cc or Bcc; participant:@example.com matches the domain of each
  address exactly, as Gloda's LIKE '%@domain' does (@example.com no longer matches example.community), and
  commas list alternatives for companies with several domains. Operators and quoted phrases combine:
  participant:@example.com subject:"invoice 42" (#17).
• searchMessages threadOf: { messageId, folderPath }: the whole conversation across folders (Sent included),
  oldest first. Headers are read first and then joined by References (union-find), so the result does not depend
  on folder order. A Re: message without threading headers joins by subject only the earlier message whose
  author (or, for own mail, a recipient) it involves (linkedBy: "subject"), so the same mail sent separately to
  several companies and repeated notifications stay apart. It reads at most 10,000 headers (the search limit) and
  sets incomplete: true when it stops there. See docs/thunderbird-internals.md (#17).
• searchMessages groupBy: "sender" | "thread": one row per sender or conversation, with count, unread, the
  first and last date, and latestId / latestFolderPath, the newest message that is not a draft (#17).
• format: "table" ({ columns, rows }) for searchMessages, getRecentMessages, searchContacts, listEvents
  and listTasks: fewer tokens on long lists (#17).
• searchMessages tag accepts a tag's label (Important) as well as its key ($label1) (#17).
• searchBody reports the terms Gloda leaves out (under 3 characters) in warning, and errors instead of running
  an empty full-text query; its description says that only English words are stemmed (#17).
• getMessage / getMessages: maxBodyChars and bodyOffset page long bodies and raw sources (#17).
• rawSource names its charset in rawCharset: strict UTF-8, else the charset of the top-level Content-Type,
  then those of the parts, else Thunderbird's charset detector. Encodings that cannot decode a whole message are
  refused, declared or detected: the "replacement" labels (iso-2022-kr, hz-gb-2312, ...), UTF-16 and
  x-user-defined. warning says when parts declare different charsets (listed in rawMixedCharsets) or when
  invalid UTF-8 was replaced with U+FFFD. rawEncoding: "base64" returns the exact bytes instead, for 8bit/binary
  parts; its pages are multiples of 4 characters, so each one decodes on its own. Before, 8-bit sources came back
  as Latin-1 mojibake (#17).

Changed

• Tool results are compact JSON (no indentation). Hidden characters left in them are written as \uXXXX escapes: in
  what the untrusted-content handling only counts (id, folderPath, filePath, dupLocations, and latestId /
  latestFolderPath, see below) and in the results of the tools it does not clean (folder, account or filter names,
  ...). The value is the same once parsed, so an id passed back unchanged still finds the same message or folder,
  but the character is visible in the text. The bridge passes compact results through unchanged. An older bridge
  (0.10.1 or earlier) paired with this extension undoes the escaping: it parses...