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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile is covered. The description adds that results are code lists and scoped by category, but says nothing about the shape of each entry (code plus label? raw slugs only?) and there is no output schema to fill that gap.

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?

Two sentences, no filler. The enumeration of valid code families comes first and the calling guidance second, which is the right order for a lookup tool.

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 single-optional-parameter reference tool with full annotation coverage, the description covers what is listed, how to narrow it, and when to invoke it. Only the per-entry return shape is left unstated, a minor gap given the tool's simplicity.

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% and the 'which' array is already documented as 'Only these lists; omit for all.' The description still earns credit by glossing the terse enum values: cities are municipality slugs, sites are plot conditions, features are project elements, areas are requirement areas — meaning the schema alone does not convey.

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 resource (valid codes for a project profile) and enumerates exactly which code families are returned: uses, stages, cities, sites, features, roles, areas. An agent can immediately tell this is a reference/lookup tool, distinct from siblings like project_overview or search_norms.

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?

Gives an explicit trigger: 'Call before project_overview or project_requirements if unsure of a code,' naming two sibling tools and the condition that selects this one. The conditional framing also implicitly tells the agent when it can skip the call.

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