list_crs_by_region

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It mentions 'purpose-based recommendations' which suggests some advisory functionality, but doesn't clarify whether this is a read-only operation, what permissions might be required, how results are structured, or any rate limits. For a tool with 3 parameters and no annotation coverage, this leaves significant behavioral gaps.

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 efficiently structured in two sentences. The first sentence states the core purpose, and the second provides helpful region-specific examples. There's no wasted text, and the information is front-loaded with the main functionality stated first.

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 has 3 parameters with 100% schema coverage but no annotations and no output schema, the description provides adequate basic context about what the tool does and some region examples. However, for a tool that apparently provides 'purpose-based recommendations' (suggesting some complexity), the description doesn't explain what form these recommendations take or how results are structured, leaving gaps in completeness.

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 documents all parameters thoroughly. The description adds some context by mentioning specific CRS examples for Japan and Global regions, which relates to the 'region' parameter, but doesn't provide additional semantic meaning beyond what's in the schema descriptions. This meets the baseline for high schema coverage.

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's purpose: 'Get available CRS list for a region with purpose-based recommendations.' It specifies the verb ('Get'), resource ('CRS list'), and scope ('for a region'), and provides examples for Japan and Global regions. However, it doesn't explicitly differentiate from sibling tools like 'search_crs' or 'recommend_crs' in terms of functionality boundaries.

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 implies usage context by mentioning 'purpose-based recommendations' and providing region-specific examples (Japan includes Plane Rectangular CS, Global includes WGS84 and UTM zones). However, it doesn't explicitly state when to use this tool versus alternatives like 'search_crs' or 'recommend_crs', nor does it mention any exclusions or prerequisites for usage.

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