start_scan_job

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

Annotations provide readOnlyHint, openWorldHint, idempotentHint, and destructiveHint. The description adds valuable behavioral context: durability, background execution, immediate return, and resumption from checkpoints after server restart. This enriches the agent's understanding beyond the annotations without contradiction.

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 concise with three focused sentences. The first sentence states the core action, the second provides usage guidance, and the third explains post-invocation behavior and resilience. No unnecessary 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?

Given the tool's complexity (3 parameters, no output schema), the description explains the overall workflow and resilience but omits details about parameter semantics, response format, and error scenarios. It is adequate for basic understanding but incomplete for full autonomous use.

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 0%, and the description does not explain any of the three parameters (account, folders, max_messages). It fails to add meaning beyond the schema structure, leaving the agent without guidance on parameter usage or constraints.

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 'Start a durable background header scan and return immediately', specifying the verb (start) and resource (background header scan). It distinguishes from sibling tools like scan_mailbox by emphasizing that it returns immediately and runs in the background, making it clear for async use cases.

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 explicitly says 'Use this for large scans from remote clients that impose request timeouts', providing a clear use case. It also advises polling with get_scan_job. While it doesn't state when not to use it (e.g., for small synchronous scans), the guidance is specific and helpful.

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