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 adds value beyond them by disclosing the return payload (profile, scores, linked accounts), which matters because there is no output schema. It says nothing about rate limits or auth prerequisites, keeping it under a 5.

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 short sentences, the payload statement front-loaded and the routing hint second. Every clause earns its place with no filler.

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 carries the burden of describing returns, and it does so at a summary level (profile, scores, linked accounts). Annotations cover the behavioral profile. The only gap is that it does not sketch the shape of 'linked accounts' or 'scores', so it is complete enough to select and call but not to anticipate the response.

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?

The tool takes zero parameters, which is the baseline-4 case. The description reinforces this implicitly by scoping the result to 'the API key owner' rather than accepting identifiers, so the parameterless contract is unambiguous.

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 ('Get the Connect profile') plus exactly what is included (scores, linked accounts) and whose data it is (the API key owner). This scope — key-owner's own identity, zero parameters — cleanly separates it from siblings like connect_scores_by_account, connect_scores_by_username, and connect_trust_graph.

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?

'Use to identify which user the key belongs to' gives a clear trigger condition for calling the tool. It does not name alternatives or state when NOT to use it (e.g., when you already have a username and should use connect_scores_by_username instead), so it stops short of the top tier.

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