v0.12.0 — State Snapshot & Diff

What's new

Feature 027: State Snapshot & Diff

Four new MCP tools for capturing and comparing debug state — enables the "snapshot → act → snapshot → diff" workflow that replaces manual variable comparison across multiple tool calls.

snapshot_create — capture current frame state:

• Records all local variables, arguments, and this for the current frame
• Accepts an optional label (e.g., "before-retry")
• Returns a snapshot ID, timestamp, thread ID, and variable count

snapshot_diff — compare two snapshots:

• Returns structured change list: added variables, removed variables, modified variables (with before/after values)
• Empty result when nothing changed

snapshot_list / snapshot_delete — manage snapshots:

• List all captured snapshots with ID, label, timestamp, and frame metadata
• Delete individual snapshots or clear all

Example workflow:

snapshot_create(label="before-fix")  →  snap-001
# step through code, modify state
snapshot_create(label="after-fix")   →  snap-002
snapshot_diff(snap-001, snap-002)    →  {modified: [{name: "retryCount", from: "2", to: "3"}]}

Also includes CI test stabilization for timing-sensitive tests on Windows and macOS.

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Full Changelog: v0.11.0...v0.12.0