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

Beyond the readOnly/idempotent annotations it discloses that verification is external and multi-source (issuer's Stellar anchor account plus OpenTimestamps checked against the Bitcoin block itself), enumerates the possible verdicts (kept_its_word, no_badge_yet, invalid), and states cost and auth ('Free, no key'). It also names the security caveat that a URL can be copied, which explains why the proof path exists.

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 core is front-loaded and the nonce workflow is ordered correctly, but the opening roleplay hook ('May I see your Word Pass?') and the long run-on verification sentence add bulk. Several clauses could be tightened without losing meaning.

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?

Covers the external checks, verdict vocabulary and the nonce/proof security path, which is sufficient for a schema-rich read-only tool with no output schema. A minor gap: with zero required parameters it never states the invariant that at least one of url or agent_id must be supplied.

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 baseline is 3; the description earns more by explaining the relationship between parameters that the schema lists atomically — url vs agent_id as alternatives, and proof/nonce as a paired holder-proof flow generated by prove_word_pass. It does not describe the internal shape of the proof object, which remains opaque.

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?

Concrete verb+resource: verify a Word Pass by checking signature, Merkle proof, Stellar root and OpenTimestamps anchor, returning a verdict. Distinguishes itself from prove_word_pass by naming it as the producer of holder proofs, but it never differentiates from other similarly named siblings such as verify_pass, get_pass or verify_licence.

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 an explicit trigger ('Before you trade with an agent you do not know, ask for its Word Pass and check it here') and an explicit conditional alternative workflow ('to be sure the pass is theirs, give them a fresh random nonce, ask for a holder proof (prove_word_pass) and pass proof and nonce here'). The agent knows when to call it, what other tool feeds it, and why the nonce path exists.

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