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diff

Show recent file changes and which symbols were added, modified, or removed. Complements git log with structured, symbol-level attribution. Use it to see which definitions were touched by recent work — useful for bug triage, code review, and onboarding to a repo mid-flight.

Parameters​

NameTypeRequiredDefaultDescription
sincestring"24h"Time window as a Go duration (24h, 1h, 30m, 7d is not supported — use 168h). Max 720h.
limitnumber50Maximum diffs to return. Range 1–500; out-of-range values silently reset to 50.
scopeenum"impl""impl", "test", or "all".

Validation​

  • since must be a valid Go time.Duration string. Invalid durations return an MCP tool error (e.g. "1 day" is rejected; use "24h").
  • Values above 720h (30 days) are clamped to 720h.
  • Invalid limit is not an error — it silently defaults to 50.

Note: Go duration strings cover "ns", "us", "µs", "ms", "s", "m", "h". Day/week units aren't supported by the standard parser.

Output​

Returns a JSON array of diff records. Each record describes:

  • The changed file.
  • Timestamp of the change.
  • Change type (add, modify, delete, rename).
  • Line counts (added / removed).
  • Affected symbols, each with its name and change type (added, modified, removed, signature_changed).

Newest-first. Capped by limit.

Example invocations​

// What changed in the last day?
{ "name": "diff", "arguments": {} }

// The last hour's worth
{ "name": "diff", "arguments": { "since": "1h" } }

// Last 3 days of changes, test files only
{
  "name": "diff",
  "arguments": { "since": "72h", "scope": "test", "limit": 100 }
}

When diff isn't the right tool​

  • You want a full commit-level history with messages and authors → use git log directly.
  • You need the textual diff content (patch) → diff returns symbol-level metadata, not unified diffs.
  • You want to know what a specific symbol's callers used to look like → diff surfaces change metadata but not historical content.

Source of truth​

  • Tool registration: internal/mcp/tools.go — diffToolDef / diffHandler.
  • Query: core.LookupDiffs.