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

With no annotations to carry the burden, the description discloses meaningful behavior: the association grants no authority, unlinking is the account's withdrawal, the action produces an auditable event, and retries are idempotent. This gives the agent a realistic model of effects and safety without contradicting the schema.

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?

Three dense sentences with no filler. The action, statement name, behavioral caveats, idempotency, and link/unlink asymmetry are all covered in compact prose that front-loads the verb and resource.

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?

For a mutation tool with no annotations and no output schema, the description covers purpose, state effect, auditability, idempotency, and the linking constraint. It stops short of full completeness by not specifying how the statement is composed from the parameters, notably created, which an agent would need to construct the signature.

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 only 25%; the description compensates for the signature parameter by explaining the statement type and the current signing key, but it does not clarify the semantics of created, subject_id, or controller_public_key beyond their field names and patterns. Some added value, but not full compensation for the low coverage.

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 description opens with a concrete verb and object: 'Withdraw one controller association', and names the exact signed statement (term-controller-unlink-v0). It further disambiguates from linking by stating linking is REST-only and not carried by this mirror, so an agent can identify the tool's role among related controller operations.

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 provides a clear when-not: linking controllers is REST-only and requires the controller's own signature, which this mirror does not hold. However, it does not explicitly name or route among sibling tools such as cancel_delegation or revoke_credential, leaving some selection guidance to inference.

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