feat(config): explicit per-tool routing for shared-language LSP servers#228
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…ervers Add name and handles fields to [[lsp_servers]] so two servers sharing a language_id (e.g. pyright for navigation, pylsp for diagnostics) can each own a distinct subset of MCP tools instead of one silently shadowing the other. Introduces ServerId, ToolKind, and ToolRouter to resolve (language, tool) to a server, validate routing conflicts at startup, and rebind dead routes to a live catch-all after registration. Also consolidates the React language-ID mapping (typescript/tsx and javascript/jsx variants) into a single source of truth shared by config extension mapping and translator dispatch, replacing two independent hardcoded match arms. Closes #174, #165
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Pull request overview
This PR extends mcpls’s configuration and bridge layers to support explicit per-tool routing when multiple LSP servers target the same language/files, while also tightening correctness around multi-server document sync and consolidating React language-id mapping.
Changes:
- Add
name+handlesto[[lsp_servers]], plus new routing types (ServerId,ToolKind,ToolRouter) to resolve(language, tool) → serverand validate ambiguity at startup. - Refactor
Translator, server init/registration, diagnostics pumping, andDocumentTrackerso the same file can be synced to multiple servers without clobbering caches. - Create a single shared React language-id mapping source (
config/language.rs) used by both config extension mapping and translator fallback routing.
Reviewed changes
Copilot reviewed 16 out of 16 changed files in this pull request and generated 4 comments.
Show a summary per file
| File | Description |
|---|---|
| examples/mcpls.toml | Adds a commented example showing name/handles usage for two Python servers. |
| docs/user-guide/configuration.md | Documents name/handles semantics, valid routing tool names, and startup ambiguity rules. |
| crates/mcpls-core/tests/integration/rust_analyzer_tests.rs | Updates integration setup to install a router and use ServerId. |
| crates/mcpls-core/tests/integration/basic_tests.rs | Adds fixture-based tests for routing + mutually-exclusive heuristics applicability. |
| crates/mcpls-core/tests/fixtures/configs/two_server_routing.toml | New fixture config demonstrating split routing for Python servers. |
| crates/mcpls-core/tests/fixtures/configs/mutually_exclusive_heuristics.toml | New fixture config demonstrating workspace-scoped applicability rules. |
| crates/mcpls-core/src/lsp/lifecycle.rs | Keys server init results by ServerId and threads IDs into spawn failure reporting/tests. |
| crates/mcpls-core/src/lib.rs | Builds a workspace-scoped router, registers servers by ServerId, and gates diagnostics caching per server. |
| crates/mcpls-core/src/error.rs | Adds NoServerForTool, changes ServerInitializing to carry ServerId, and enriches spawn failure display. |
| crates/mcpls-core/src/config/server.rs | Extends LspServerConfig with name/handles and adds id() derivation. |
| crates/mcpls-core/src/config/routing.rs | New routing module implementing typed tool routing, validation, and post-spawn rebind behavior. |
| crates/mcpls-core/src/config/mod.rs | Wires in routing + React mapping modules and adds validation for name/handles. |
| crates/mcpls-core/src/config/language.rs | New single source of truth for React language-id variants and inverse mapping. |
| crates/mcpls-core/src/bridge/translator.rs | Routes tool calls via ToolRouter, keys client/server maps by ServerId, and applies React fallback consistently. |
| crates/mcpls-core/src/bridge/state.rs | Tracks per-server sync state (synced) so one path can be didOpen/didChange-synced independently to multiple servers. |
| CHANGELOG.md | Documents the new routing feature and breaking API changes. |
The unit/integration/e2e test steps never passed --profile ci, so the retries=2 and 180s slow-timeout already defined in .config/nextest.toml for CI went unused; every run fell back to the default profile's 120s ceiling with no retries. This PR roughly doubled the fake_lsp_client() subprocess-backed tests in bridge/state.rs, and on the two-core windows-latest runner the ones that wait on actual child-process wire I/O started tripping that ceiling.
disk_phase and disk_phase_new checked a file's size against a separately-stat'd metadata() call, then read the same path again via a new open. A concurrent atomic replace between those two calls could substitute a larger file after the size gate passed, defeating the pre-read size limit. read_to_string_checked now opens the file once and stats/reads through that single handle, so the size gate and the read observe the same file consistently. Also corrects the CHANGELOG's Translator API entry, which named a router() accessor that was never added (the actual methods are with_router, rebind_router, and is_diagnostics_route).
bug-ops
enabled auto-merge (squash)
July 25, 2026 01:32
This was referenced Jul 25, 2026
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Summary
nameandhandlesfields to[[lsp_servers]]so two servers sharing alanguage_id(e.g. pyright for navigation, pylsp for diagnostics) can each own a distinct subset of MCP tools instead of one silently shadowing the other.ServerId,ToolKind, andToolRouterto resolve(language, tool) -> server, validate routing conflicts at startup (over applicable configs per workspace, not globally), and rebind dead routes to a live catch-all after server registration completes.didOpen/didChangeon both and doesn't clobber the diagnostics cache.typescript/tsx,javascript/jsxvariants) into a single source of truth shared by config extension mapping and translator dispatch, replacing two independent hardcoded match arms that could silently drift apart.Closes #174, closes #165
Breaking changes (pre-1.0, documented in CHANGELOG.md under
[Unreleased]):Error::ServerInitializing/Error::NoServerForTool,Translator'sServerId-keyed maps and renamedset_expected_servers,DocumentTracker::ensure_open's newserver: &ServerIdparameter,lsp::ServerInitResult.serverskeying, andworkspace_symbol_searchdispatch order (now config declaration order instead ofHashMapiteration order). Two servers sharing alanguage_idwith no disambiguating routing now hard-fails at startup instead of silently dropping one.Test plan
cargo +nightly fmt --all -- --checkcargo clippy --all-targets --all-features --workspace -- -D warningscargo nextest run --workspace --all-features(467/467 passing)RUSTDOCFLAGS="-D warnings" cargo doc --no-deps --all-features(rustdoc gate)NoServerForTool),register_serversrebind-before-diagnostics-flags regression,ServerConfig::validate()rules, mutually-exclusive-heuristicsfixture (loads when only one server is applicable, fails at startup when both are)