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

Annotations already cover idempotency, destructiveness, and open-world scope, so the description adds genuine extra context: conflict behavior on a competing active claim, automatic lease expiry, and the absence of a background reconciliation worker. The only omission is any statement of what a successful claim returns, which matters for an acquisition call.

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?

Five tight sentences, each front-loaded with an operative fact: claim action, required identifier, conflict outcome, token retention, expiry behavior. No filler or restatement of the name.

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 compensates by disclosing the conflict signal (claim_conflict) and the lease-token lifecycle, which are the facts an agent needs to handle a claim correctly. Nothing critical is missing for a 6-parameter acquisition tool.

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 83%, so the schema carries most parameter meaning; the description still adds lifecycle semantics by tying session_id to 'this Codex run' and instructing the caller to retain and reuse lease_token for renew/update. That is value beyond the field descriptions, lifting it above the baseline 3.

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 ('atomically claim a task/handoff') and immediately establishes the concurrency semantics that distinguish it from sibling relay_read_thread/relay_post. An agent can tell this is the acquisition step of a lease workflow without inspecting 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?

Explains the precondition ('session_id must identify this Codex run') and routes the agent forward by naming relay_update/renew as the consumer of lease_token. It does not explicitly say when NOT to call it versus a sibling like relay_post, but the usage context is clear.

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