Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Goes well beyond the annotations: it explains that this is a real execution through the actual registry with the same guards and audit trail (not a simulation), that the scratch workspace is wiped and the scenario replayed, and that persisted conformance evidence is refreshed. That resolves the ambiguity of readOnlyHint=false / destructiveHint=false / idempotentHint=false for the caller.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Front-loads the core action and the response shape, then adds effects last. It is slightly longer than needed — the 'refusal steps teach more than the happy path' aside is advisory rather than operational — but no sentence is filler.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With no output schema, the description still enumerates what the response contains (act, command, arguments, expectation, and actual result) and discloses all side effects, so an agent knows exactly what it gets back and what state it changes.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so both parameters are already documented, including the o2c default and the pointer to core_spec_status for valid file names. The description adds no parameter-level meaning beyond that, so the baseline 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('Replay one spec scenario live in its scratch workspace') plus the return shape ('step-by-step evidence'). It also distinguishes itself from the nearest sibling by pointing at core_spec_status for the scenario list, so an agent can pick correctly without opening the schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives a clear use context ('Show it to someone learning the area') and notes the refusal steps are the most instructive. It does not state explicit when-not conditions or name an alternative tool for the 'just list scenarios' case beyond the parameter hint, so it falls short of a 5.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.