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Gaunt Sloth Documentation

MCP_FAIL_CLOSED_ANNOTATIONS

const MCP_FAIL_CLOSED_ANNOTATIONS: Readonly<EffectiveToolAnnotations>

Defined in: _worktrees/docs-release/gaunt-sloth/packages/core/src/core/approvals/matcher.ts:138

The MCP fail-closed defaults (spec §4.7.2): a tool that has said nothing about itself is assumed to write, to destroy, to be non-idempotent and to reach the open world. These are the values the MCP specification itself defines for absent annotations, so an entry written against them is written against the protocol’s own conservative reading.

Frozen, and read-only to the type system, because it is shared: an effective set is something callers snapshot (§4.7.4 records one on a sticky grant), so a source that handed this object out instead of a copy would let one caller’s snapshot rewrite the fail-closed floor for every other. Freezing turns that aliasing bug into an immediate throw rather than a silent, global loosening.