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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint, so the safety profile is covered. The description still adds real context beyond them: 'Free, no key' discloses that no authentication/credential is required, and it documents exactly what the verification performs (PazAIr signature, Merkle proof into the day's root, Bitcoin and Stellar anchors).

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?

Two sentences, front-loaded with the core purpose and the 'low level' framing, followed by the alternative-routing rule. No filler; every clause carries 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?

For a low-level cryptographic verification tool with no output schema, the description explains what is checked and implicitly that it returns raw evidence rather than a verdict (contrasting check_word_pass 'which also gives a verdict'). The remaining gap is the shape of the return value, but the agent has enough to invoke it correctly.

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 0%, so the description must carry the parameter burden. It enumerates all three inputs (pass, proof, day) inline and frames them as the raw Word Pass object, which is more than nothing, but adds no format, structure, or required-vs-optional detail.

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 (verify a raw Word Pass object), and immediately distinguishes itself from the sibling check_word_pass by scoping the input to a pass the caller already holds. The agent can tell this apart from get_pass, prove_word_pass and check_word_pass without opening any 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?

Explicitly names the alternative and the condition that selects it: 'Holding only an agent_id or a Word Pass URL? Use check_word_pass, which also gives a verdict.' This is a when-to-use-this/when-to-use-the-other routing rule, not inferred guidance.

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