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

Annotations already indicate read-only, non-destructive, idempotent behavior. The description adds meaningful behavioral details: it returns a short answer plus which policy/document was used, includes a financial-advice disclaimer, never returns PDS text or document bodies, and requires vault.read. These go well beyond the annotations and set clear expectations for an agent.

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 no wasted words. It front-loads the core action, then lists return contents, constraints, and the required permission in a logical order. Every sentence carries useful 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?

For a simple two-parameter tool with no output schema, the description explains what will be returned, what will never be returned, the required permission, and the relationship to list_policies. This is sufficient for an agent to invoke the tool and interpret the result correctly.

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 explains both parameters. The description's mention of 'policy_id hint from list_policies' overlaps with the schema's own 'from list_policies' text, adding little new semantic value beyond the word 'hint,' which is minor.

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 opens with a specific verb and resource: 'Ask a natural-language coverage question about the connected vault.' It clearly distinguishes this tool from siblings like list_policies or ingest_document by framing it as a Q&A tool that returns answers rather than raw policy data or documents.

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 clear context for when this tool is appropriate: when the user has a natural-language coverage question. It also hints at a workflow by mentioning policy_id comes from list_policies. However, it does not explicitly state when not to use it or name alternative tools for cases like listing policies or ingesting documents.

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