coord_transform_crs

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

The description adds substantial behavioral context beyond the annotations: it discloses that the tool reports the exact PROJ transformation and accuracy, explains what ballpark=true means in practical error terms, and reveals that missing_grids identifies unavailable grid files. It also documents the always-x/y axis-order convention, which is valuable operational information.

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 dense but every sentence earns its place: purpose, supported systems, accuracy caveats, and axis-order rule. It is front-loaded with the primary action and avoids filler or redundant restatement of the schema.

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 read-only, idempotent transform tool with an output schema, the description covers all important operational concerns: supported CRS scope, transformation accuracy, missing-grid behavior, and axis order. Nothing critical appears missing for an agent to select and invoke the tool 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 baseline is 3. The description adds meaning beyond the schema by clarifying that inputs and outputs are always x/easting first and y/northing second regardless of CRS axis order, which directly informs how x and y parameters must be supplied. This lifts it above the baseline.

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 core action with a specific verb and resource: 'Transform coordinates between any two coordinate reference systems.' It names supported CRS families and 'any other EPSG-registered CRS,' but it does not explicitly distinguish this tool from the sibling coord_convert, so it stops short of full sibling 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 gives clear context for when to use this tool: whenever coordinates need transforming between CRSs, with national grids, Web Mercator, and any EPSG-registered system named as examples. It does not provide explicit exclusions or name alternatives for when not to use it, so it earns a 4 rather than a 5.

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