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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so safety and repeatability are covered. The description adds the useful detail that a single record is returned and names the fields, but says nothing about missing-permit behavior, rate limits, or error handling beyond what annotations provide.

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?

A single front-loaded sentence with no filler: it leads with the lookup action and key, then the returned fields. Every clause earns its place.

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 read tool with safety annotations already in place, the description covers purpose, keying, and return fields, which compensates for the absent output schema. The remaining gaps are the parameter formats and not-found behavior, which are minor for this tool's complexity.

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%, so the description must carry the full parameter burden. It does convey that permit_id is a city permit number and that the two parameters form a scoped key, but neither parameter's format (e.g., expected permit-number pattern) nor the city's accepted value form is explained, leaving meaningful ambiguity.

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 (look up), a specific resource (one building permit), and the key (city permit number), and enumerates the returned fields (work, date, status, cost, address). The word 'one' plus the permit-number key clearly separates it from the list-oriented siblings permits_at_address and recent_permits.

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?

Usage is implied rather than stated: looking up 'by its city permit number' signals it is for the case where the agent already has a permit number, which implicitly rules out permits_at_address. However there is no explicit when-to-use statement, no mention of the sibling tools, and no guidance on what to do when the number is unknown.

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