One finding, and a sharp one: position in the stream is not causation.
`collectSkillInvocations` flattened every `tool_use` block across every
assistant event into one ordered array, and `chainHit` read position
alone. But the model can emit several `Skill` blocks in a SINGLE assistant
message, and it has not seen the first skill's body when it does — those
are parallel guesses, not a hand-off. A run that emitted `testing` and
`test-servers` together in one message scored as `A` led to `B`, and would
have gone on scoring after the pointer in `testing`'s body was deleted:
exactly the false pass this feature exists to rule out, arriving by a
second route (Copilot).
Each recorded invocation now carries the assistant event it came from —
`{payload, turn}` — and `chainHit` requires every link after the first to
land in a STRICTLY later turn. The turn count is threaded through
`collectSkillInvocations`'s `turnOffset`/`nextTurn` so a stream read in
chunks stays monotonic rather than restarting per read; without that, a
chunk boundary would reset the numbering and reintroduce the same bug on
long runs.
The scan stays greedy, which is still correct under the constraint: taking
the earliest occurrence of a link can only leave more room for the rest,
so no later starting point succeeds where the greedy one fails.
`sampleHit` is deliberately unaffected — a first-move case asks only
whether a skill fired at all, so it reads names and ignores turns.
Four new assertions in one case: a same-turn pair scores false; the same
two skills a turn apart score true; a same-turn pair does not poison a
later genuine hand-off; and only the chain's first link is unconstrained.
Plus a `collectSkillInvocations` case pinning the turn tagging and the
cross-chunk offset.
`docs/skill-authoring.md` now lists this as the second way a chained case
can false-pass, alongside a prompt carrying the target's own trigger.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01ABdTnqyBodw6mHVVkGehqe
Signed-off-by: cliffhall <cliff@futurescale.com>
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