Renew free TLS certificate

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

Annotations cover the safety profile, but the description adds substantial context beyond them: approval is required, issuance is asynchronous so the agent must poll get_free_certificate, an ambiguous response means re-read state before retrying (corroborating idempotentHint=false), and certificates:manage permission is required. This is exactly the extra behavioral detail annotations cannot carry.

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-loaded with the action and each clause (approval, async polling, retry rule, permission, key non-disclosure) earns its place. Dense but not padded; a reader can extract the operational rules in one pass.

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 tells the agent the operation is permission-gated, asynchronous, poll-based, and non-destructive to the private key. Nothing needed to invoke or follow up on this call correctly is missing.

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 coverage is 100%, so the baseline is 3. The description adds real meaning beyond the schema by explaining that csr is only required for customer_csr certificates, that it must cover the same authorized names, and that no private key is ever returned, which the schema itself does not state.

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?

Specific verb (renew) plus resource (owned free TLS certificate) and scope (early renewal). It cleanly distinguishes itself from get_free_certificate, create_free_certificate, cancel_free_certificate, and revoke_free_certificate siblings without the agent needing a 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 the trigger ('request early renewal ... after reading its current state'), the branch condition (customer_csr needs a new CSR; managed-key normally auto-renews, implying when not to use), and an explicit alternative/polling tool (get_free_certificate). Both when-to-use and when-not are covered.

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