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

Beyond the annotations (destructiveHint=true), the description adds valuable behavioral context: it discloses that the prior draft is snapshotted to version history first, making the operation recoverable, and explicitly mentions the API key requirement. This reduces risk for the agent and directly addresses the destructive nature of the tool without contradicting the annotations.

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 three sentences with the core action front-loaded. Each sentence earns its place: the action and modes, the API key requirement, the recoverability guarantee, and the pointer for section keys. There is no fluff or repetition of schema content.

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 write tool with no output schema and a simple parameter set, the description covers the essential context: what it does, modes, auth requirement, recoverability, and how to obtain a required parameter. It doesn't describe the response or error behavior, but that is not critical given the simplicity and the fact that annotations already flag destructive 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 coverage is 100%, so the baseline is 3. The description adds meaning by telling the agent to use get_my_application to see section_keys, clarifying the source of the section_key parameter. This goes slightly beyond the schema's own description by providing a workflow pointer, justifying a 4.

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 action ('Write content into one section') and the resource ('your grant application') with explicit modes of 'replace or append'. This is specific enough to distinguish it from most siblings, though it does not explicitly name alternatives like draft_application_section, so it lacks the full 5-level differentiation.

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 provides practical guidance on what to do first ('Use get_my_application to see section_keys') and notes a prerequisite ('Requires your API key'). It does not explicitly state when to use this tool versus alternatives like draft_application_section, nor does it mention situations where this tool should not be used, leaving usage context implied rather than explicit.

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