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

Annotations declare readOnlyHint=false and destructiveHint=false, confirming a non-destructive mutation. The description adds value beyond them with an auth requirement ('Needs your API key') and a hard uniqueness constraint (one identity per agent / one agent per identity), which is the main source of failure. It says nothing about what happens on a duplicate attempt or about the retry/idempotency behavior the schema exposes.

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?

Three short sentences, no filler, with the action and its verification mechanism front-loaded before the constraints. Every sentence carries distinct 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?

There is no output schema, but the description says what the server does (verifies with world keys, links the stable id) and names the auth prerequisite. Missing are the failure/duplicate-link semantics and confirmation of the return payload, though these are minor for a two-required-param write.

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 100%, so connectorId, proof, and idempotencyKey are all documented in the schema itself. The description adds no format, ordering, or sourcing detail beyond that, which is the expected baseline of 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+resource ('Submit the proof... links the world's stable id to your agent') and makes the outcome explicit. It is clearly distinguishable from the sibling get_world_identity_challenge, which supplies the challenge this tool consumes.

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?

The first sentence implies the precondition (you must have a challenge/proof issued by the world) and the constraint 'One world identity per agent, and one agent per world identity' effectively states when the call will not succeed. It does not name the sibling alternative explicitly, so it falls just short of a 5.

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