setup_credentials

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

The annotations declare idempotentHint=true, meaning multiple calls have the same effect; the description confirms this only implicitly by saying it 'saves to persistent config file,' implying it can be re-run. The description does not detail behavior beyond this (e.g., overwriting, error handling), but with idempotentHint present, the bar is lower. The description adds value by specifying the config is persistent, which aligns with idempotency.

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 description is extremely concise: two short sentences plus a clear action prompt. Every sentence serves a purpose—defining the tool, providing a source, and noting persistence. No wasted words.

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 simple setup tool with 100% schema coverage and idempotentHint annotation, the description is complete enough. It covers purpose, source, and outcome. It lacks details on what happens if credentials are invalid or if it's called repeatedly, but given the tool's simplicity and prior annotations, this is adequate. A score of 5 would require explicit error/conflict behavior.

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 the schema already documents all three parameters with good descriptions. The description adds extra context by specifying the config file persistence and providing a URL for obtaining the credentials. However, the parameter names and schema descriptions are clear, so the description adds modest incremental value. A higher score would require more unique parameter insights.

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?

The description clearly states the tool's purpose: configuring FatSecret API credentials. It specifies the verb ('Configure'), the resource ('FatSecret API credentials'), and provides a direct source for obtaining them. This is distinct from all sibling tools, which focus on food, recipe, weight, exercise, or auth endpoints, making the purpose unambiguous.

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 description implicitly guides usage by indicating this is a setup step ('Saves to persistent config file'), suggesting it should be run before using other tools. However, it does not explicitly state when to use this versus alternatives—though given the uniqueness of a credential-setup tool among siblings, this gap is minor. It would benefit from stating 'should be called once before other API calls' or 'needed once before using other tools.'

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