docs: tune skill eval cases and document how to write them

`skills:eval` was at 38/46 with several skills measuring 0-33%. The low
scores were mostly bad eval cases rather than bad descriptions, for two
reasons that were nowhere written down:

- The harness runs each case with `--max-turns 1`, so the skill has to be
  the model's FIRST tool call. A prompt asking "how does X work here", or
  naming a concrete file, sends the model to Read/Grep first — a better
  answer to the question, scored as a miss. Every 0% case was one of these.
- `AGENTS.md` is resident on every turn, so a prompt it already answers is
  answered without any skill and the case can never pass.

Replace the cases that measured the wrong thing, expand every model-invoked
skill from 3 to 5 positives (negatives kept) so one flake cannot cross the
threshold, and reshape `local-dev`'s description to the action-first form.

Add `docs/skill-authoring.md` with the case shapes that fire, the ones that
cannot, and the probe-then-measure loop.

RUNS=5 npm run skills:eval: 63/63 at or above threshold, 60 at 100%,
all 18 negatives clean.

Closes #2202

Signed-off-by: cliffhall <cliff@futurescale.com>
This commit is contained in:
cliffhall 2026-08-31 23:22:25 -04:00
commit 6dd43e78ba
13 changed files with 262 additions and 9 deletions

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@ -11,6 +11,14 @@
"prompt": "The project board rejected my Status option ID. How do I get the current ones?",
"expect": "board-ops"
},
{
"prompt": "I'm about to edit the options on one of the board's single-select fields. Should I do anything first?",
"expect": "board-ops"
},
{
"prompt": "Several cards lost their Priority value after the field was edited. How do I put it back?",
"expect": "board-ops"
},
{
"prompt": "Explain the difference between TCP and UDP.",
"expect": null

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@ -11,6 +11,14 @@
"prompt": "Before I file this, how do I check nobody has reported it already?",
"expect": "issue-create"
},
{
"prompt": "I found a bug while working on something else. How do I get it tracked in this repo?",
"expect": "issue-create"
},
{
"prompt": "What do I need to do beyond `gh issue create` for a new issue to be properly tracked here?",
"expect": "issue-create"
},
{
"prompt": "What is the chemical symbol for potassium?",
"expect": null

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@ -4,13 +4,21 @@
"expect": "issue-triage"
},
{
"prompt": "What Priority should issue 2189 be given?",
"prompt": "How do I decide what Priority an incoming issue deserves?",
"expect": "issue-triage"
},
{
"prompt": "Audit the project board for anything that has drifted.",
"expect": "issue-triage"
},
{
"prompt": "How do I find the issues that aren't on either board yet?",
"expect": "issue-triage"
},
{
"prompt": "After scoring an issue against the rubric, what do I do with the score?",
"expect": "issue-triage"
},
{
"prompt": "Who wrote the novel Moby-Dick?",
"expect": null

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@ -1,6 +1,6 @@
---
name: local-dev
description: Getting the Inspector running locally, and the reasoning behind its dependency rules. Which install to run and which script starts each client (web, cli, tui, launcher); why v2 is not an npm workspace; how the @inspector/core alias works; and why the placement rules in AGENTS.md are what they are — what each one is defending against, what it looked like when it was violated, and how to tell you have hit one.
description: Install, build and run the Inspector locally, and place a dependency correctly. Use when starting the web, cli, tui or launcher client; when asking whether a build or rebuild is needed before a run script works; when an install, an @inspector/core import or a client bundle fails at run time; when adding or bumping a dependency and choosing which package.json declares it; or when a bundler external, a version skew or a git worktree is the suspect.
disable-model-invocation: false
---

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@ -15,6 +15,10 @@
"prompt": "How do I run the CLI from the built launcher in this repo instead of via npx?",
"expect": "local-dev"
},
{
"prompt": "I just pulled and a client's dependencies look out of sync. What do I need to run?",
"expect": "local-dev"
},
{
"prompt": "Write a haiku about autumn.",
"expect": null

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@ -11,6 +11,14 @@
"prompt": "The DCO check is red on my branch. How do I fix the commits I already pushed?",
"expect": "pr-flow"
},
{
"prompt": "Copilot left a pile of review comments on my PR. How do I answer them so nothing gets lost?",
"expect": "pr-flow"
},
{
"prompt": "My PR is open and green. Walk me through getting it merged and closed out here.",
"expect": "pr-flow"
},
{
"prompt": "What does this regex match? /^[a-z]+$/",
"expect": null

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@ -4,13 +4,21 @@
"expect": "pre-push-gate"
},
{
"prompt": "The Storybook stage of the gate fails in my worktree even though the tests pass. What is wrong?",
"prompt": "The gate's Storybook stage is failing for me. How do I diagnose it?",
"expect": "pre-push-gate"
},
{
"prompt": "Everything in the gate started timing out at once. What causes that?",
"expect": "pre-push-gate"
},
{
"prompt": "How do I check whether a stage of the gate really passed?",
"expect": "pre-push-gate"
},
{
"prompt": "The gate failed at the lint stage. How do I work out what is wrong?",
"expect": "pre-push-gate"
},
{
"prompt": "What is 17 multiplied by 23?",
"expect": null

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@ -4,11 +4,19 @@
"expect": "project-structure"
},
{
"prompt": "I'm adding a helper both the CLI and the web client need. Which directory does it belong in?",
"prompt": "Does a new Node-only backend piece for the web client belong in core or in the web client itself?",
"expect": "project-structure"
},
{
"prompt": "Which package owns the OAuth secret storage backends?",
"prompt": "Does browser-only transport code belong in core or in the web client?",
"expect": "project-structure"
},
{
"prompt": "I have a new file and I'm not sure where it goes. How do I decide in this repo?",
"expect": "project-structure"
},
{
"prompt": "Does a helper that only the CLI and TUI use belong in core or in one of the clients?",
"expect": "project-structure"
},
{

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@ -11,6 +11,14 @@
"prompt": "I renamed a file under test-servers/src and the fixture is still running the old code. Why?",
"expect": "test-servers"
},
{
"prompt": "Which protocol era should I connect with when I run one of these fixtures by hand?",
"expect": "test-servers"
},
{
"prompt": "I need a fixture combination that doesn't exist yet. How do I add one?",
"expect": "test-servers"
},
{
"prompt": "Sort this list alphabetically: banana, apple, cherry.",
"expect": null

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@ -1,16 +1,24 @@
[
{
"prompt": "I just added clients/tui/__tests__/serverList.test.ts. What command runs only the TUI suite?",
"expect": "testing"
},
{
"prompt": "In clients/web/src/components/Foo.test.tsx I need to assert on a Mantine transition mid-flight. How?",
"expect": "testing"
},
{
"prompt": "Which test tier in this repo spawns the built binary rather than importing it?",
"expect": "testing"
},
{
"prompt": "How do I run just the TUI suite, and is there one command that runs everything?",
"expect": "testing"
},
{
"prompt": "How do I write a test for a TUI component in this repo?",
"expect": "testing"
},
{
"prompt": "How am I supposed to invoke the CLI from a new test in this repo?",
"expect": "testing"
},
{
"prompt": "How do I run the web integration tests, and do they run as part of the normal test command?",
"expect": "testing"
},
{
"prompt": "What does this regex do? /^\\d{3}-\\d{4}$/",
"expect": null

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@ -192,6 +192,9 @@ that from happening:
a skill therefore has a cost paid by the *existing* ones, which only
`skills:eval` can see. **Re-run the full eval after any flip _or description
edit_**, not just the changed skill's own cases.
**How to write a description that fires, and cases that measure it, is
[`docs/skill-authoring.md`](./docs/skill-authoring.md)** — the case shapes
that work, the ones that can never pass, and the probe-then-measure loop.
The lever that works is the description's *shape*. Leading with the actions
and then enumerating concrete situations ("Use when … ; when … ; when …")
beats a noun-phrase list of contents: it took `pre-push-gate` from 3/5 to 5/5
@ -230,7 +233,7 @@ that from happening:
overflows, and drops the least-invoked entries **first** — which are exactly the
model-invoked skills that must fire on their own. `verify:skills` prints the
current cost against the budget recorded in `scripts/lib/skill-manifest.mjs`
(2,834/4,000 characters as of this writing) and fails when it is exceeded. Raise
(2,921/4,000 characters as of this writing) and fails when it is exceeded. Raise
the budget deliberately, or tighten a description; each entry is capped at 1,536
characters regardless, so **put the key use case first**.

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@ -70,6 +70,7 @@ Each client has its own README with client-specific detail:
| --- | --- |
| [Architecture](./docs/architecture.md) | The `@inspector/core` shared package, and the web client's "dumb components" + Storybook approach |
| [Testing and the quality gate](./docs/quality-gate.md) | What each `validate` / `coverage` / `smoke` / `verify:*` script covers, the GitHub-CI-vs-local-gate split, and the supported browsers |
| [Writing a skill](./docs/skill-authoring.md) | How to write a skill description that actually fires, and eval cases that measure it — the case shapes that work, and the tuning loop |
| [Test servers](./docs/test-servers.md) | The composable test servers and the showcase config for every feature — what to run, what to click, and what the broken build did |
| [Publishing](./docs/publishing.md) | What ships in the tarball, the packaging invariants, and `pack:verify` |
| [Docker](./docs/docker.md) | Running the container image — ports, volumes, and where secrets go |

181
docs/skill-authoring.md Normal file
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@ -0,0 +1,181 @@
# Writing a skill and its eval cases
The **rules** for skill maintenance — the four numbered requirements, the
invocation-mode policy, the listing budget — are in
[`AGENTS.md`](../AGENTS.md#maintaining-the-skills). This page is the _how_: what
makes a description fire, what makes an eval case measure the right thing, and
the loop for tuning both. It exists because `verify:skills` can prove a skill is
well-formed but cannot prove it is ever _reachable_, and the tool that measures
reachability — `npm run skills:eval` — reports a hit rate rather than a verdict.
## How the eval actually measures
`scripts/skill-eval.mjs` runs every committed case in a **fresh headless
session** (`claude -p`), `RUNS` times, and scores the fraction of runs in which
the `Skill` tool fired with the expected name.
Four properties of that harness drive everything below:
- **`--max-turns 1`.** The skill must be the model's **first** tool call. If it
opens a file first — even on its way to a perfect answer — the sample is a
miss. This is the single most important fact about writing cases.
- **The session is fresh, but not empty.** `CLAUDE.md` → `AGENTS.md` is loaded
in full on every turn, so anything the rules file already answers gets
answered without a skill.
- **Negative cases are scored against every model-invoked skill in this repo**,
not just the one whose file they live in. A negative passes only if _none_ of
ours fired.
- **Positive cases may only expect their own skill.** `verify:skills` rejects a
foreign name, because a case that passes when a _different_ skill fires
reports a measurement of something it does not describe.
## Writing a description
Lead with the **actions**, then enumerate concrete **situations**:
```
description: <verb phrase saying what this does>. Use when <situation>;
when <situation>; when <situation>; or when <situation>.
```
This shape is what the measurements keep rewarding. Reshaping `pre-push-gate`
into it took it from 3/5 to 5/5, and `testing`'s three cases from 25/50/25% to
100% each. A noun-phrase list of contents ("Where things live, what is in core/,
and what each directory is for") consistently underperforms it.
Three further rules, each learned the expensive way:
- **Put the key use case first.** Each listing entry is capped at 1,536
characters and the whole listing at 4,000; entries are dropped least-invoked
first when it overflows.
- **Adding a skill costs the skills already there.** Going from three
model-invoked skills to nine measurably lowered the trigger rate of the
existing ones — the ceiling is attention, not characters. So **re-run the full
suite after any flip or description edit**, never just the changed skill's
cases.
- **`paths` is not a free win.** It halved `testing`'s conversational trigger
rate, and a prompt-only eval can never exercise a path trigger, so shipping it
means shipping an untestable claim.
## Writing an eval case
### The first-move rule
A case measures the description only if invoking a skill is the model's natural
**first** move. Ask **"how do I …"**, not **"how does this work"** — the second
invites a `Read` or a `Grep`, which spends the only turn the harness allows.
Measured, one probe each, on this repo:
| Prompt | First tool call |
| ---------------------------------------------------------------------------------------- | --------------- |
| "How do TUI components get mounted and keypresses driven in this repo's tests?" | `Bash` |
| "How do I write a test for a TUI component in this repo?" | `Skill` ✅ |
| "Which part of this repo owns the browser's HTTP transport and the backend it talks to?" | `Bash` |
| "Does browser-only transport code belong in core or in the web client?" | `Skill` ✅ |
| "Which parts of the gate only ever run locally and never in CI?" | `Read` |
| "The gate failed at the lint stage. How do I work out what is wrong?" | `Skill` ✅ |
Shapes that reliably fire:
- **"How do I …"** — a procedure, not an explanation.
- **"Does X belong in A or B?"** — a decision the repo has a convention for.
- **"\<Stage\> failed. How do I diagnose it?"** — a symptom with a documented cause.
- **"Which command runs …?"** — when the answer is a repo-specific script.
- **A bare imperative** — "Triage the new issues.", "Move the card for issue 2189
to In Review."
Shapes that reliably do not:
- **"How does X work here?"** / **"Where is X implemented?"** — an invitation to
read the source, which is the _better_ answer and scores as a miss.
- **Anything naming a concrete file, symbol, or helper.** Naming the mechanism
hands the model a grep target and removes the reason to load a procedure.
### Do not write a case `AGENTS.md` already answers
`AGENTS.md` is resident on every turn, so a prompt it answers is answered
without the skill and the case reads as a permanent miss. Two that had to be
retired here:
| Retired case | Why it could never pass |
| ------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------- |
| "Which package owns the OAuth secret storage backends?" | The directory tree in `AGENTS.md` says `auth/ — OAuth end to end + the per-server SecretStore backends`. Scored 0% across two full runs. |
| "In `…/Foo.test.tsx` I need to assert on a Mantine transition mid-flight. How?" | `AGENTS.md` names `renderWithMantineTransitions` and states the rule outright. Also named a concrete file — two faults at once. |
| "What should I run before I push?" | `AGENTS.md` states `npm run local:gate` is the mandatory pre-push command. Scored 40%. |
The test to apply before committing a case: **could a reader answer this from
the rules file alone?** If yes, it measures `AGENTS.md`, not the skill. Aim the
case at what only the skill body holds — a live ID, a command sequence, a
recovery recipe, a diagnosis.
### When a neighbouring skill fires, the case is wrong
A positive case may only expect its own skill, so a prompt that a _different_
skill legitimately owns can never pass — and rewriting the description to win it
would be the wrong fix, because it would broaden a skill onto another's ground.
"How do I get an issue I already filed onto the project board with the right
fields?" fired `board-ops` 3/3 as an `issue-create` case. `board-ops` is the
right answer: adding a card and setting its fields is a board operation. The
case was replaced, not the description.
Before blaming a description for a miss, check **which** skill fired. If it is a
neighbour and the neighbour is right, the case is aimed at the wrong skill.
### Negative cases
Every skill file needs at least one `"expect": null` case; a skill that fires on
everything is a context regression nobody notices by hand. Keep them plainly
unrelated to the repo (arithmetic, trivia, a one-line refactor). All 18 in this
repo have held at 100% through every reshaping so far — if one starts firing, a
description has grown too broad.
## The tuning loop
**Probe first, then measure.** A full suite run is ~63 cases × `RUNS` sessions
of metered model calls; a single probe is one. Iterate with probes until a
prompt fires at all, and only then spend a full run on its rate:
```sh
# One sample, printing which tool actually fired first.
print -r -- "<prompt>" \
| claude -p --output-format stream-json --verbose --max-turns 1 --allowedTools "Skill" \
| grep -o '"name":"[^"]*"' | head -3
```
**Probe a marginal case more than once.** A prompt that fires on a single probe
can still measure 60% over five runs — one sample cannot distinguish "reliable"
from "coin flip". Three probes is enough to tell a solid replacement from a
lucky one, and it is still far cheaper than a full suite run.
Then the suite:
```sh
npm run skills:eval # every model-invoked skill, RUNS=3
RUNS=5 CONCURRENCY=6 npm run skills:eval
npm run skills:eval -- testing # one skill's cases (still scores negatives against all)
```
**Read the noise before reading the result.** At `RUNS=3` one sample is worth 33
points, and an untouched skill was observed swinging 100 points across two runs
of the same suite. `RUNS=5` is the smallest setting where a single flake does
not cross the 0.8 threshold on its own. A one-case move is not evidence; a skill
whose cases move _together_ is.
This is why the eval is **not** in `validate`, `local:gate`, or CI: it spends
metered calls, it is non-deterministic by construction, and it goes red on a
rate limit. A case below threshold is a signal to investigate, not a build
break.
## Checklist for a new or edited skill
1. Frontmatter opens on line 1 (no BOM, no blank line), YAML is valid — an
unquoted colon in a description loads the body with an _empty_ description,
so `/name` still works while the skill can never auto-fire again.
2. `disable-model-invocation` is declared explicitly; default it to `false`.
3. Description is action-first, with `Use when …; when …; when …`.
4. `evals/evals.json` has both positives and at least one negative, every
positive shaped by the first-move rule and none answerable from `AGENTS.md`.
5. `npm run verify:skills` passes and the listing is under budget.
6. `RUNS=5 npm run skills:eval` — the **whole** suite — is ≥80% on every case,
including the skills you did not touch.