#116691 taught the runtime (`_get_platform_tools`) to read the
`'["browser", "terminal"]'` string an older `hermes config set` stored as
the user's real toolset selection, but the two other readers of the section
kept the old `isinstance(raw, list)` gate:
- `validate_platform_toolsets` (hermes doctor / startup warnings) reported
"invalid toolset value ... falling back to 'hermes-cli'" for a value the
runtime resolves to browser+terminal — a false warning.
- `plugins_cmd._toggle_plugin_toolset` skipped the string entry, so
`hermes plugins enable <p>` never reached that platform.
- `nous_subscription._toolset_enabled` treated it as an empty list.
Move the list-literal parse into one function,
`toolset_validation.parse_platform_toolsets_value`, and route all four
readers through it; the plugin toggle re-saves the entry as a real list so
the string never persists past the next write. `_coerce_platform_toolsets_value`
keeps its once-per-platform warning for values that do not parse.
Why one parser: three readers with three notions of "configured" is exactly
how #115866 went unnoticed. Follow-up to #116691 (independent review finding).
validate_platform_toolsets() accumulated a single valid_count across every
platform, so the "zero valid toolsets" safety net was suppressed as soon as any
one platform carried a valid toolset. A platform wiped to [] — the active one,
typically cli — therefore produced no warning at all.
resolve_enabled_toolsets() honours that empty list verbatim ([] is a list, so
the platform-default fallback is skipped), leaving the agent with zero tool
schemas. The model then has nothing to call and emits the tool call as
assistant text with finish_reason=stop: no error, no warning, no log entry.
That is the silent-failure mode this module was written to prevent (#38798).
Note the asymmetry this leaves intact: a malformed *string* value is not a list,
so it falls back to the platform default and fails open (#78103); an empty list
fails closed. The fail-closed resolution is deliberate (the explicit_empty_
selection contract in tools_config.py, and #82010 wants it persistable), so this
only adds the missing warning and does not change resolution semantics.
Fixes#89050
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
A config migration (or hand-edit) that leaves an invalid toolset name in
`platform_toolsets` — e.g. the #38798 corruption that rewrote `hermes-cli` to
the non-existent `hermes` — silently disabled all affected tools:
resolve_toolset() returns [] for an unknown name, so the agent quietly lost its
tools with no error, warning, or log entry and degraded to text-only replies.
Surface it loudly at two points:
- After migration (migrate_config): validate platform_toolsets and record/print
a warning per unknown name, with a `hermes-<platform>` suggestion when that
would have been valid (the exact #38798 shape).
- At runtime (_get_platform_tools): if a platform was explicitly configured but
every toolset name is invalid, log a warning when tools are resolved for a
session — so an ALREADY-corrupted config is caught at startup, not only on the
next `hermes update`.
Logic lives in a new pure, side-effect-free helper (toolset_validation.py) with
validate_toolset injected, so it is unit-testable without the tool registry.
Note: the original v25→v26 migration that caused the corruption no longer
exists (config format is now v30; no migration step rewrites toolset names).
This change is the durable defense against the silent-failure mode regardless
of cause, matching the issue's "Expected: log a warning".
Salvaged from #39207 by @lEWFkRAD (authorship preserved via cherry-pick).
Tests: 9 helper cases (incl. the #38798 corruption shape, mixed valid/invalid,
zero-tools state, non-dict/scalar/non-string) + a runtime caplog test — both the
helper warning and the runtime guard mutation-verified to fail without the fix.
Closes#38798. Supersedes #39581 (prevent-in-v25→v26 — that path is gone),
#41006 / #40208 (repair-migration for already-corrupted configs).
