* feat: emit structured runtime metadata
* fix: avoid subagent import cycle in replay gateway
* fix: preserve legacy subtask result parsing
* refactor: tighten runtime metadata contracts
* fix(middleware): keep recovery hint on task exception wrapper content
The structured-metadata stamp overwrote the wrapper text with the bare
task-failure message, dropping the model-facing 'Continue with available
context, or choose an alternative tool.' guidance that every other tool
exception keeps. Append the shared hint after the formatted message.
* fix(subagents): require lowercase hex for result_sha256 reader
Length-only validation accepted any 64-char string; a faulty serializer
or relaying wrapper could store a non-digest value in the delegation
ledger. Enforce the producer's hexdigest shape with a fullmatch.
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Co-authored-by: Willem Jiang <willem.jiang@gmail.com>
* feat(subagents): add delegations ledger field + reducer to ThreadState
* feat(subagents): pure helpers to derive + format the delegation ledger
* feat(subagents): DelegationLedgerMiddleware records + injects the ledger
* feat(subagents): register DelegationLedgerMiddleware for lead when subagents enabled + docs
* add runtime log
* chore(subagents): make delegation-ledger injection log production-ready
* test(subagents): make delegation-ledger registration tests config-free; refresh ultra replay golden for delegations channel
* refactor(subagents): derive TERMINAL_STATUSES from SUBAGENT_STATUS_VALUES + pin it
Make thread_state's TERMINAL_STATUSES a frozenset over the status contract's
SUBAGENT_STATUS_VALUES instead of a hardcoded literal, so the terminal-status
set can never drift from the contract. Add a pinning test asserting the
derivation and that the non-terminal "in_progress" stays excluded.
Addresses PR #3877 review.
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Co-authored-by: Willem Jiang <willem.jiang@gmail.com>
