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

Annotations already declare readOnly/idempotent/non-destructive, so the bar is lower; the description still adds real context — that verification is offline-style, requires no key, and is free. It hints that the tool returns raw sub-results rather than a single verdict ('which also gives a verdict'), but doesn't spell out the result shape.

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?

One tight paragraph, front-loaded with the tool's identity and scope, followed by cost/auth facts and the sibling hand-off. No sentence is redundant with the schema or annotations.

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 nested-object, no-key, read-only verification tool with no output schema, the description covers scope, trust model ('offline-style'), cost, and the alternative. The only real gap is what a caller gets back — per-check booleans vs. aggregate — left implicit by the contrast with check_word_pass's 'verdict'.

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, but the description goes further by tying pass/proof/day to distinct verification steps (signature, Merkle path into the day's root, root anchors), explaining why the optional proof and day inputs matter. It stops short of format or optionality guidance beyond what the schema states.

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 (check/verify) and resource (a raw Word Pass object you already hold) and enumerates exactly what is verified: PazAIr signature, Merkle proof into the day's root, and the Bitcoin/Stellar anchors. The word 'Low level' plus the closing pointer to check_word_pass cleanly separates it from that sibling.

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?

Explicit use condition ('check a raw Word Pass object you already hold') and an explicit alternative with its own condition ('Holding only an agent_id or a Word Pass URL? Use check_word_pass'). The agent can route between the two without opening either schema.

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