git:20260923.dd5dbaa to git:20260924.fa28c43

- This directory is wiring, not logic. Two files: `hooks.json` registers the

- events, `run.mjs` is the one entry point every hook and the MCP server go

- through. The behaviour lives in TypeScript under `mcp/src/hooks/` and ships

- compiled as `dist/hooks/<name>.js`. Editing a hook almost always means editing

- `mcp/src/hooks/`, not here.

-

- ## `run.mjs` is the launcher

-

- `.sh` hooks are unreliable on Windows, so every entry in `hooks.json` — and

- `.mcp.json` — is `"command": "node"` with

- `["${CLAUDE_PLUGIN_ROOT}/hooks/run.mjs", "<name>"]`: `node.exe` is a real

- executable and needs no shell. Keep that shape; `mcp/test/packaging.test.ts`

- asserts the server entry is exactly that string.

-

- `run.mjs` maps `<name>` to `dist/hooks/<name>.js` (`server` → `dist/server.js`)

- and resolves it, most specific first: `EKLAVYA_RUNTIME`, then the checkout's own

- `mcp/dist` (only when `mcp/node_modules/better-sqlite3` exists), then

- `~/.eklavya/runtime/node_modules/eklavya`. In a development checkout your local

- build wins — so rebuild before you test. With no build reachable, `server` falls

- back to `npx eklavya@<pinned> serve` and a hook starts a detached background

- `npm install` (once an hour at most, claimed by a `.installing` stamp before

- spawning) and exits 0 saying nothing.

-

- The same heal keeps an **installed** runtime current. The plugin moves when

- Claude Code updates it; the runtime only moves when npm runs. So when the entry

- resolved to `~/.eklavya/runtime` and its `package.json` version is older than

- `plugin.json`'s, `healIfBehind` starts that background install before the

- import — this run still uses the old runtime and never waits. It never

- downgrades (migrations only go forward), leaves an `EKLAVYA_RUNTIME` or

- checkout build alone, and does nothing when the global config says

- `auto_update: false` — read straight from `config.json`, since the runtime's

- config loader is not reachable here. A *missing* runtime is healed regardless:

- that is bootstrap, not an upgrade. `eklavya doctor`'s `versions` row reports the

- skew.

-

- The `.installing` stamp is the one runtime lock, shared with `installRuntime`

- and the updater; `mcp/src/install-lock.ts` states the rules and `run.mjs`

- carries a copy, because it has to work before any runtime exists. After

- spawning npm the heal rewrites the stamp to name npm's pid, so the claim lives

- exactly as long as npm runs; the stamp npm leaves behind also throttles the heal

- to once an hour. `mcp/test/install-lock.test.ts` races all three entry points

- against a fake npm.

-

- The `npx` fallback retries `eklavya@latest` once, and only when npm says the

- pinned version does not exist (`E404`/`ETARGET`/`No matching version`). That is

- the release gap: semantic-release pushes the bumped `plugin.json` in its

- `prepare` step, before `npm publish`, so a marketplace pull can pin a version

- npm does not have yet for a minute or so. A server that started and then failed

- is not restarted.

-

- **It carries no version number.** It reads `.claude-plugin/plugin.json` at

- runtime, and `mcp/test/packaging.test.ts` asserts the file matches no

- `\d+\.\d+\.\d+` anywhere and does match `plugin\.json` — so writing any dotted

- triple in here, even in a comment, fails that test on purpose.

- `scripts/bump-version.sh` bumps `plugin.json` and `mcp/package.json`, nothing

- else.

-

- ## The seven hooks, out of `hooks.json`

-

- Seven scripts on six events: `checkpoint-quiz` is registered twice under

- PostToolUse, so the table has eight rows.

-

- | Event | Matcher | Timeout | Script | Job |

- |---|---|---|---|---|

- | SessionStart | — | 10s | `session-start` | stamp this checkout's session pointer (`meta.current_session:<repo root>`), replay the spool, summarise the last session's batch, recall this project's memory, start the background auto-update when one is due (`update.ts`) and add its one line — `Eklavya updated to X` once, or `Eklavya can't update itself · … · run: eklavya update` every session while it fails — to what the developer sees, show the developer the profile banner (`systemMessage`) and hand the model the recall and the standing log directive (`additionalContext`). A database that exists but will not open gets one line to the developer — `Eklavya paused · can't open its database · run: eklavya doctor`, or the SQLite/Node-mismatch variant — and a first run with no database stays silent |

- | UserPromptSubmit | — | 10s | `prompt-submit-nudge` | re-stamp this checkout's session pointer, then re-state the log directive in one line, but only for a session that has logged nothing after a grace window |

- | SubagentStart | — | 10s | `subagent-start` | give a delegated agent the log directive the parent's SessionStart never reached it with |

- | PreToolUse | `Bash` | 10s | `pre-tool-gate` | with `quiz.enforced` only, deny a `git commit` (or `git merge --continue`) whose session gate has not passed. `commit-lib.ts` lexes the command like a shell — newlines, `env`/`sudo`/`timeout`/`VAR=x` prefixes, `bash -c`, subshells, substitutions, `git -C dir` — and accepts missing aliases and scripts: the git hook is the real enforcement |

- | PostToolUse | — | 10s | `capture-tool` | record the tool use as memory evidence |

- | PostToolUse | `mcp__.*log_session_concepts` | 10s | `checkpoint-quiz` | one mid-task question, `interleaved` cadence only |

- | PostToolUse | `^(Bash\|Edit\|Write\|MultiEdit\|NotebookEdit)$` | 10s | `checkpoint-quiz` | the same hook, re-armed by the work: the model logs once per task, so without this the checkpoint asked once per task. No `statusMessage` — it would flash on every command |

- | Stop | — | 15s | `stop-quiz-check` | block the turn and demand a quiz — this session's concepts first, then this project's backlog (`backlogConcepts`, shared with the planner), never backlog under `quiz.enforced` |

-

- ## Memory capture is not governed by `quiz`

-

- `capture-tool` has no matcher, so it runs after **every** tool call — it is the

- hook that fires most often in a session, and it does the least: resolve

- identity, normalise one event, one insert, exit. It never quizzes, summarises

- or calls a provider.

-

- Four hooks now carry memory work, and all four do it **before** their `quiz`

- check, because `memory.enabled` is a separate decision from the learning dials

- (PRD CFG-01): `quiz.enabled: false` means no quizzes, not no project history.

- That separation is why the `mode` dial was retired — it was always true and the

- word `off` denied it, so `session-start` now says on screen which half stopped.

- `session-start` replays the spool and recalls; `prompt-submit-nudge` captures

- the prompt; `capture-tool` captures the tool use; `stop-quiz-check` closes the

- batch at the seam. `mcp/src/hooks/memory-lib.ts` holds the shared helpers, and

- every one of them swallows its own failures — a capture path that throws is a

- throw on every tool call. The light capture path — `identityOf`, `record`,

- `batchIfFull` — lives in `capture-lib.ts`, so `capture-tool` and

- `prompt-submit-nudge` never import the worker, the provider, recall or notify;

- `memory-lib.ts` re-exports them for the seam hooks, and

- `mcp/test/hook-isolation.test.ts` fails if a hot path starts loading a heavy

- module again.

-

- A Stop seam does not close a batch every turn: only at `SEAM_MIN_EVENTS` (8)

- or once the oldest open event is `SEAM_MAX_AGE_MS` (20 minutes) old, because

- with an observer configured every closed batch is a `claude -p` call. A session

- start closes everything. The same seam runs the retention sweep

- (`pruneIfDue`, at most every six hours, 5,000 events at a time) and gives all

- notification sinks one shared 5s budget (`NOTIFY_BUDGET_MS`).

-

- The seam never waits on inference. With `providers.observer` configured,

- `flushAtSeam` queues the batch and hands it to a detached `eklavya memory

- process` — but only after winning the single machine-wide worker reservation

- (`mcp/src/memory/reservation.ts`), and never while the queue is paused. A Stop

- hook that waits on an API call is exactly what PRD LRN-04 forbids.

-

- **Every hook is inert inside Eklavya's own `claude -p`.** The observer sets

- `EKLAVYA_INTERNAL_OBSERVER=1`, and `run.mjs` and `run()` in `lib.ts` both exit 0

- before reading stdin. Claude Code 2.1.280 ran plugin hooks inside `claude -p`

- despite `disableAllHooks`, each helper's seam spawned a worker, and a 16 GB Mac

- reached 165 workers. `--safe-mode` now suppresses them too, but correctness

- rests on the env check: never move it after anything that opens the database

- or spawns. `mcp/test/memory-observer-guard.test.ts` runs a stand-in `claude`

- that executes every hook anyway.

-

- The PostToolUse matcher on `checkpoint-quiz` is a regex over the MCP tool name, not a literal, because

- the prefix depends on how the plugin was installed —

- `mcp__eklavya__log_session_concepts` standalone,

- `mcp__plugin_eklavya_eklavya__log_session_concepts` via `/plugin`. `mcp__.*`

- catches both; anchoring it to one spelling silently disables the checkpoint for

- half the installs.

-

- ## Two audiences, two channels

-

- Every line a hook writes is for the developer or for the model, and each has

- exactly one channel: top-level `systemMessage` is rendered to the developer,

- `hookSpecificOutput.additionalContext` is read by the model. Plain stdout is

- never used. On `SessionStart` it is accepted, but as context only — the banner

- went out that way for months and every session opened in apparent silence while

- the model read three lines meant for a person. And `systemMessage` is **top

- level**: nested inside `hookSpecificOutput` the harness drops it, which is how

- the checkpoint's one line to the developer went unseen for just as long.

- `docs/verified-schemas.md` has the per-hook table; `mcp/test/hooks.test.ts`

- asserts on `shown` and `context` separately, and its `systemMessage()` helper

- throws on the nested placement, so a new hook cannot repeat either mistake

- without a test saying so.

-

- ## SubagentStart needs the JSON form, and skips the tutor

-

- `SessionStart` accepts raw stdout as context (Eklavya no longer uses it — see

- above). `SubagentStart` does not: it

- reads `hookSpecificOutput.additionalContext` and drops anything else in silence,

- so the wrong form is a hook that runs, exits 0, and does nothing. That is the

- one thing `subagent-start.ts` cannot get wrong, and `mcp/test/hooks.test.ts`

- parses the envelope rather than asserting that something was printed.

-

- It also stays silent for `eklavya-tutor`, matched as a substring so both

- `eklavya-tutor` and `eklavya:eklavya-tutor` are caught. Not because the tutor

- lacks `log_session_concepts` — so do `Explore` and `Plan`, and they are told

- anyway. It is the directive's second sentence: *do not ask the developer

- anything here* is an order not to do the only thing `agents/tutor.md` exists

- for, so delivering it disables parallel tutoring in silence. An absent or

- unrecognised `agent_type` fails **open** — a host that does not send the field

- is a host where failing closed would turn the feature off with nothing to

- report. `docs/subagent-policy.md` is the policy in full; keep the two in step.

-

- `stop-quiz-check.ts` carries the same `agent_id` guard as `checkpoint-quiz.ts`,

- and for a stronger reason: it keeps the turn going. `Stop` is believed to be

- parent-only, since `SubagentStop` is a separate event — but nothing here has

- verified that, and this hook is what made the path reachable, because before it

- a subagent logged nothing and the Stop hook's `logged > last_logged` predicate

- could never arm. Do not read that as making the guard optional now: under

- `interleaved` the clock arms the sweep whether or not anything was logged, so the

- `agent_id` check is the only thing standing between a subagent and a quiz it

- cannot ask.

-

- **And it pays the stdin cost on every delegated task.** It needs `agent_type`,

- so it cannot keep ponytail's stdin-independent fast path; on a host that

- swallows the pipe that is `idleMs` — 2s — per subagent spawn, the same trade

- `PreToolUse` makes per `Bash` call.

-

- ## Every failure path exits 0

-

- A hook that throws breaks the user's session, and a learning tool that breaks

- sessions gets uninstalled. `run()` in `mcp/src/hooks/lib.ts` enforces it: parse

- stdin defensively, run the body, exit 0 silently on any throw. A new hook body

- goes inside `await run(async (input) => { ... })` and returns an exit code; it

- never calls `process.exit` itself. Helpers follow the same rule —

- `openExisting()` returns `null` rather than throwing on a missing or corrupt

- database, and deliberately does not migrate or seed (several hooks racing a

- migration on session start is a corruption story). Every hook returns 0 — the

- Stop sweep included. It keeps the turn going with

- `hookSpecificOutput.additionalContext` rather than exit 2, because exit 2 renders

- to the developer as a hook error; `docs/verified-schemas.md` D1 has the table.

-

- ## A hook must never *wait*, either

-

- Exiting 0 on a throw covers the loud failure. The quiet one is worse: a hook

- that blocks never errors, never logs, and stalls the session on every tool call

- that triggers it — with nothing for the developer to report except that Claude

- Code got slow.

-

- `readInput` used to be `for await (const chunk of process.stdin)`, which has

- exactly one exit: EOF. Ponytail's issue #443 reports Claude Code on Windows

- running a hook through a PowerShell block that swallows the piped JSON, so `end`

- never fires. **Nothing here verifies that mechanism** — there is no Windows

- machine in the loop — so what this defends against is the consequence, a stdin

- that never ends, which the tests reproduce directly. `run.mjs` is careful about

- everything else — Node version, four resolution candidates, a self-expiring heal

- claim, exit 0 on every throw — and this was the one gap.

-

- `mcp/src/stdin.ts` closes it, and `eklavya statusline` shares it: both read a

- JSON blob the host pipes in, both must degrade rather than hang, and two copies

- would be one copy getting the fix. Three things matter about it.

-

- **The primary bound is on silence, not on total time.** A flat cap truncates a

- payload still arriving when it fires, and truncated JSON does not fail loudly —

- it fails as `{}`, so the hook runs to completion having quietly decided the

- session has no cwd and no id. The idle timer resets on every chunk, so a payload

- is safe as long as it keeps making progress. The total cap behind it *can* still

- truncate, and claiming otherwise would be the same overclaim in the other

- direction — it is a deliberate trade, and `totalMs` is generous against how long

- a real payload takes.

-

- **It pauses the stream, not just the listeners.** This is the line the rest of

- it depends on. `setEncoding` puts stdin in flowing mode and a flowing stdin holds

- an active libuv handle, so removing the `data` listener resolves the read and

- leaves the process alive. The hooks hide that — `run()` ends in `process.exit` —

- but `eklavya statusline` just returns, and under exactly the no-EOF condition

- this exists for it printed the dials and then lingered forever, once per status

- bar refresh. `test/stdin.test.ts` spawns the statusline for that reason: it is

- the caller with no `process.exit` behind it, so it is the honest test of whether

- the read lets go.

-

- **Every timer is `unref`'d**, so a pending timer adds no latency to a hook that

- has already finished. On its own that does not let the process exit — see above.

-

- **There is an `error` handler.** A stream that errors never emits `end`, so

- without one the read waits on something that is not coming. It is also

- load-bearing beyond that: an unhandled `error` on `process.stdin` is an async

- exception `run()`'s `try`/`catch` could not have caught.

- **It costs something, and the cost is worth stating.** On a host that swallows

- the pipe this turns an infinite hang into `idleMs` per invocation, and PreToolUse

- matches every `Bash` call — so +2s per command until the host is fixed. Two

- seconds a command is bad; a frozen session is worse.

- `HOOK_STDIN` is 2s idle / 5s total, well under the 10s `hooks.json` grants (15

- for Stop) — a read that outlives its host timeout is a read the developer waits

- on, and `test/stdin.test.ts` asserts the relationship rather than the number.

- `STATUSLINE_STDIN` is 150ms / 250ms, and the total is pinned at or below the

- 250ms flat cap the inline reader had before it: splitting one budget into idle

- plus total made the worst case four times worse for the one caller whose latency

- a human sees, which a test now prevents.

- That suite spawns a real hook, writes a payload, and **never closes stdin**;

- against the old code all three cases hang until the test kills them.

- `stripBom` runs before every `JSON.parse` here. Some Windows shells prepend a

- byte-order mark, and `JSON.parse` throws on input that looks perfectly

- well-formed in a terminal and in any editor — another silent nothing-happens.

- ## `quiet` is not an off switch

- It suppresses the session-start banner and the status bar — things the developer

- looks at. It does **not** suppress the standing directive, and it does not gate

- the `UserPromptSubmit` nudge, because both are `additionalContext` the model

- reads rather than output anyone sees.

- That was a bug for a while, and a bad one: `session-start` returned before

- pushing the directive, so a developer who turned the greeting off logged

- nothing, was never quizzed, and saw quizzing reported as enabled in

- `get_config` the whole time. Two tests encoded it as intended behaviour.

- `quiz.enabled: false` is the off switch — along with its session-scoped twin

- below, which is the same switch with a shorter life.

- ## The Stop hook blocks when unenforced too

- Commonly got wrong. Unenforced is not "never interrupts" — `stop-quiz-check.ts`

- returns 2 without the gate as readily as with it. `quiz.enforced` changes three

- things: the `min_minutes_between_quizzes` cooldown is skipped (a cooldown could

- make a commit gate unpassable — decision G5); the one-question cap under

- `interleaved` is lifted, so the sweep asks for the whole remaining budget; and

- `pre-tool-gate` plus `cli/eklavya-gate` start holding commits. Only

- `quiz.enabled: false` silences the questions — and it silences only those, not

- the memory half.

- ## The per-session off switch

- `isSessionOff(db, sessionId)` (`mcp/src/session.ts`) is a `meta` row written by

- `set_config` at `scope: "session"`. **Every hook that speaks to the developer

- checks it right after its `mode` check** — session-start, the nudge, the

- checkpoint, Stop, subagent-start. `pre-tool-gate` is the deliberate exception

- and reads it only to word its refusal; see below. It exists because the file-backed `off` outlives the urgent

- afternoon that wanted it, and a developer who silences one hour by editing a

- config file has quietly turned the product off for good.

- Two rules it is easy to get wrong:

- - It silences, it does not exempt. `cli/eklavya-gate` reads the project config and

- never sees a session id, so an enforced repo still holds the commit. Making

- the gate honour it would turn a per-session convenience into a gate bypass.

- `pre-tool-gate` reads `isSessionOff` for one reason only: its refusal tells

- the model to run a quiz, and in a silenced session the planner returns

- `session_off` and nothing to ask, so the refusal has to name the way out.

- Reading it to word the message is not the same as acting on it.

- - Enforced mode is **not** the exception here that it is for the cooldown. The

- cooldown is pacing Eklavya chose; this is the developer saying stop, in words.

- ## The loop guard

- A Stop hook that blocks on every Stop blocks forever, and `stop_hook_active` is

- no longer a documented input. What bounds it depends on the cadence, because the

- two cadences block for different reasons.

- Under **`end`**: block only when the count of `origin = 'work'` rows in

- `session_concepts` has **grown** since the last block. That cadence delivers the

- whole budget in one sweep, so a second sweep needs new work behind it.

- Under **`interleaved`**: the pacing clock is the guard. The `logged > last_logged`

- rule cannot work here — the model logs its whole batch in one call at the start

- of a task, so "new work since the last block" is false for the rest of the

- session and the sweep fired exactly once, ever. That capped a session at two

- questions against a budget of four. Time re-arms it instead.

- Either way, blocking stamps into `stop_markers` (`last_logged_count`,

- `last_blocked_at`, `block_count`) *before* the block — a failure after it costs

- a missed quiz, never a loop — and three caps bound every block: the pacing clock,

- `max_stop_blocks_per_session` (default 3), and the remaining session budget.

- Counting review-origin rows here would let answering a question re-arm the block

- that asked it; don't. `checkpoint-quiz.ts` has the mirror-image guard for

- mid-turn bursts, stamping `checkpoints` before it emits.

- ## Pacing

- Two keys, and which one applies depends on what is being paced, not on which

- hook is asking (`mcp/src/config.ts` is the source of truth).

- `min_minutes_between_checkpoints` (default 4) paces a **single question**: the

- mid-task checkpoint in `checkpoint-quiz.ts`, and the Stop sweep too whenever the

- cadence is `interleaved`, since a sweep is one question there.

- `min_minutes_between_quizzes` (default 20) paces a **whole quiz**, which only the

- `end` cadence produces. Both apply **in `ambient` only**, and both are measured

- against the last block *and* the last answer — checking only one would let the

- hook block a turn the quiz plan then refuses as too soon. That is why

- `get_session_quiz_plan` picks between the same two keys on the same cadence: the

- hook's clock and the plan's cooldown have to be the same number, or the hook

- blocks a turn and the plan hands back `questions_needed: 0`. Under `interleaved`

- the Stop sweep floors its gap at one minute, because there the clock is the whole

- loop guard and `0` is a legal value for the checkpoint it borrows.

- `max_questions_per_task` (default 4) is a session allowance shared by both hooks:

- every `attempts` row spends it, so the Stop hook asks for whatever the checkpoints

- left. The two hooks' candidate queries share a WHERE clause verbatim; if you

- change one, change both, or a concept gets asked twice or never.

- ## The SessionStart banner is a format string

- The `[Eklavya] ...` line in `mcp/src/hooks/session-start.ts` is quoted verbatim

- by `web/public/index.html` (the hero terminal script) and

- `web/src/content/docs/docs/installing.mdx` (the no-history variant). Changing its

- wording, order or fields means re-quoting both in the same commit.

- ## Testing a hook by hand

- `dist/` must exist first — the tests run the built files, not the sources, and

- `pretest` builds them. From `mcp/`:

- ```sh

- npm run build

- echo '{"session_id":"s1","cwd":"/path/to/repo","hook_event_name":"Stop"}' \

- | EKLAVYA_DB=/tmp/k.db EKLAVYA_HOME=/tmp/eklavya-home \

- node dist/hooks/stop-quiz-check.js; echo "exit $?"

- ```

- `EKLAVYA_DB` and `EKLAVYA_HOME` point a hook at a scratch database and config;

- `EKLAVYA_SESSION_ID` overrides the harness session id. `mcp/test/hooks.test.ts`

- and `mcp/test/gate.test.ts` do exactly this.