Check whether a function is a native or wrapped C closure

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the description's 'Safety: read-only' is redundant. It does add non-annotation context (cost=medium, requires=active-client/resolved-target, produces structured-observation), which is genuinely useful. It never states the return is a boolean predicate, which is the one behavioral fact an agent would want.

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?

The predicate verb is front-loaded, but the body is a dense metadata dump (phase/cost/idempotency/requires/capabilities/produces/safety) that re-states the annotation set, and the trailing 'On failure: inspect tool-schema...' is a deflection rather than a fact. It could be materially shorter and still carry the same information.

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?

This is a low-complexity read-only predicate with 100% schema coverage and no output schema, so the description needn't explain return values. Preconditions and phase are covered, leaving only the boolean return nature and sibling selection unstated. Complete enough for a tool of this complexity.

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 fully documented in the schema. The description merely restates the signature ({ functionPath: string, threadContext: number? }) without adding format, semantics, or examples beyond it. Baseline 3 is correct.

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?

The title states a precise predicate (native/wrapped C closure) and the description puts a verb on it ('Resolve a function and call iscclosure'). An agent knows exactly what it checks. However it never differentiates the sibling predicates is-l-closure, is-executor-closure, and is-new-c-closure, so it doesn't tell you which of the family to pick.

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?

It gives preconditions ('Requires: active-client, resolved-target') and a phase tag ('observe'), which implies when it fits in a workflow. But it names no alternative and gives no when-not guidance, so the agent must infer selection among the several is-*-closure tools itself.

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