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

Beyond the annotations, the description discloses critical behaviors: the call is monetized via x402 with a specific cost and network, issuance depends on principal verification, and the result ties an operator to a public key with an expiry. It also gives the exact endpoint, which is highly actionable.

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 description is three sentences and every sentence earns its place: definition, failure behavior, and payment/endpoint. Key information is front-loaded and there is no redundant restatement of the schema.

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?

The description covers the endpoint, payment, the core security property, and the output schema exists, but the low parameter coverage leaves important invocation details unexplained. For a tool with 8 required parameters, the absence of guidance on principal kinds and attestation methods makes it not fully self-sufficient.

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 9%, so the description carries the burden of explaining parameters. It provides a high-level conceptual mapping ('agent's public key', 'operator details', 'expiry', 'verified principal') but does not explain key required parameters such as principal_kind, principal_attestation_method, agent_key_scheme, or idempotency_key. An agent would struggle to choose valid values.

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 clearly identifies the verb ('Issue') and resource ('Agent ID'), and explains what the tool produces: a signed identity attestation binding an agent's public key to a verified principal. It does not explicitly compare itself to sibling tools like agentid_renew or agentid_verify, so differentiation is clear from context rather than stated.

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?

The description implies this is for issuing a new Agent ID and emphasizes that issuance is refused when the principal cannot be verified. It does not explicitly state when to use this tool versus agentid_renew, agentid_verify, or agentid_revoke, nor does it describe prerequisites beyond verification and payment.

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