Adds a per-tool optimizer finding for MCP servers whose schema is loaded
on every turn but rarely invoked. Builds on the existing server-level
`detectUnusedMcp` (zero invocations) by reporting partial-use cases:
"loaded 54 tools, called 0" or "loaded 26 tools, called 2 (8% coverage)".
Inventory comes from Claude Code's JSONL `attachment.deferred_tools_delta`
entries: `addedNames` lists the exact tools available at that turn,
including every fully-qualified `mcp__<server>__<tool>` name. We union
across all delta entries in a session (not just the first) because tool
availability can change mid-session when the user reloads MCP config or
a subagent inherits a different tool set. Names that don't match the
`mcp__<server>__<tool>` shape with both segments non-empty are rejected
at extraction so downstream `split('__')` consumers can't be poisoned.
Token-savings estimates are cache-aware. MCP tool schemas live in the
cached prefix of the system prompt: a session pays the full input price
on each cache-creation turn (rebuilds happen every ~5 minutes of
inactivity) and the cache-read discount on subsequent turns. Each call's
contribution is capped at its observed `cacheCreationInputTokens` /
`cacheReadInputTokens` so we never claim more MCP overhead than the
call's own cache buckets could contain.
When multiple servers are flagged, costing happens in a single combined
pass: the per-call cap applies to the total unused-schema budget across
all flagged servers, not per server. Two flagged servers cannot both
independently claim the same call's cache bucket, which would otherwise
overstate `tokensSaved` and misclassify findings as high impact.
A session counts toward `loadedSessions` (and toward the cost estimate)
only if its observed inventory included the server. Pure invocation-only
sessions, where the server appears in `mcpBreakdown` or `call.mcpTools`
without any matching `deferred_tools_delta`, do not satisfy the
`>= 2 sessions` threshold on their own. The same invariant applies in
`estimateMcpSchemaCost` so the two passes agree.
Coverage is computed against the inventory only: invocations of names
not present in any observed inventory (older config, hallucinated tool,
typo) do not inflate `toolsInvoked` and cannot drive `unusedCount`
negative. `toolsInvoked` is derived as `inventory.size - unusedTools.length`
to keep both numbers consistent.
`detectUnusedMcp` and the new detector are explicitly disjoint:
`detectUnusedMcp` skips servers that the coverage detector will report,
not every server that happens to be in any inventory, so a small
inventoried-but-uninvoked server below the coverage thresholds still
gets flagged as "configured but never called."
Thresholds for the coverage finding:
- > 10 tools available (small servers are noise)
- < 20% coverage
- >= 2 sessions with observed inventory
- High impact when total effective tokens >= 200_000 or >= 3 servers flagged
Smoke-tested on a real account: 7 servers flagged across 93 sessions
(`office-word-mcp` 0/54, `notebooklm-mcp` 0/38, `office-ppt-mcp` 0/37,
`excel-mcp-server` 0/25, `github-mcp-server` 2/26, `peekaboo` 3/22, plus
`claude_ai_Asana`). Combined-cap costing keeps `tokensSaved` honest.
Changes:
- src/types.ts: optional `mcpInventory: string[]` on `SessionSummary`.
Provider-agnostic field; currently populated only by the Claude parser.
- src/parser.ts: `extractMcpInventory` walks all entries, validates
fully-qualified names, returns sorted unique list. `buildSessionSummary`
passes it through; field is omitted when empty so JSON exports stay
clean.
- src/optimize.ts: `aggregateMcpCoverage`, `estimateMcpSchemaCost`
(single- and multi-server signatures), `detectMcpToolCoverage`. Wired
into `scanAndDetect`. `detectUnusedMcp` updated to disjoint with the
new detector.
- tests/mcp-coverage.test.ts: 23 cases covering aggregation, costing,
combined-cap behaviour, threshold gates, invocation-only-session
filtering, foreign-tool invocations, cache rebuild events, write+read
on the same call, multi-server pluralisation.
- tests/parser-mcp-inventory.test.ts: 12 cases for the JSONL extractor
including malformed name rejection and tolerant attachment parsing.
- CHANGELOG.md: entry under Unreleased / Added (CLI).
Closes#2
Turns whose only assistant tool is `Skill` collapse to category `general`
because `classifyByToolPattern` returns `'general'` and `refineByKeywords`
only operates on `coding`/`exploration`. In environments that lean on Claude
Code skills, the per-activity dashboard column flattens — every `/init`,
`/review`, `/security-review`, `/claude-api`, plus user-defined skills, all
land in `general` with no signal about which workflow ran.
Implements Option A from the issue:
- `ParsedApiCall.skills: string[]` populated in the Anthropic-path parser
via a new `extractSkillNames` helper that reads `input.skill || input.name`
from each `Skill` ToolUseBlock (mirrors `detectGhostSkills` extraction at
optimize.ts:765 so the two stay in sync).
- `ClassifiedTurn.subCategory?: string` set to the first skill name when the
resolved category is `general` AND any skill identifier was extracted.
Top-level category stays `general` — existing aggregations, exports, and
category-keyed code paths unchanged.
- `SessionSummary.skillBreakdown: Record<string, {turns,costUSD,editTurns,
oneShotTurns}>` populated in the same per-turn loop that builds
`categoryBreakdown`. Provider sessions (Codex/Cursor/etc.) keep `skills:
[]` — they don't expose the Skill tool surface today.
- Dashboard `ActivityBreakdown` renders top-N skill sub-rows beneath the
`general` row when present (indented `/skill-name`, dimmed). Other
categories render exactly as before; if no skills were invoked, the panel
is byte-identical to current output.
Existing 419 tests still pass. New `tests/classifier.test.ts` adds 8 cases:
single skill via `input.skill`, single via `input.name`, first-wins for
multi-skill turns, aggregation across multiple assistant calls in one turn,
no-name fallback (`subCategory` stays undefined), `Skill+Edit` promoting to
`coding` and dropping subCategory, non-Skill general turns, and a legacy
ParsedApiCall shape with `skills` field absent (forward-compat). Pre-fix
verification by stashing the source change reproduces 4/8 failures with the
exact "expected 'init', received undefined" diff; restoring → 8/8 pass.
Closes#203.
🤖 AI assistance disclosure: assistant-scaffolded by Claude (Opus 4.7);
author of record reviewed every line, ran the full vitest suite locally
(`npm test` → 32 files / 427 tests pass), `npx tsc --noEmit` clean, and
`npm run build` produces a clean ESM bundle.
Detects edit/test/fix retry cycles (Edit -> Bash -> Edit) within each
turn. Shows 1-shot percentage in the By Activity panel for categories
that involve code edits. Updated screenshot and README.
Fixes#4
Interactive TUI dashboard for Claude Code token observability.
13-category task classifier, per-project/model/tool breakdowns,
gradient bar charts, SwiftBar menu bar widget, CSV/JSON export.
