Retrieve Ordnance Survey raster map tiles using ZXY coordinates, with delivery options for inline or resource output.
Fetch a raster ZXY tile with inline/resource delivery controls.
| Name | Required | Description | Default |
|---|---|---|---|
| x | Yes | ||
| y | Yes | ||
| z | Yes | ||
| tool | No | ||
| style | No | ||
| format | No | ||
| delivery | No | ||
| inlineMaxBytes | No |
| Name | Required | Description | Default |
|---|---|---|---|
| delivery | Yes | ||
| dataBase64 | No | ||
| contentType | Yes | ||
| resourceUri | No |
Changes observed during successful MCP inspections.
v0.8.2Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint, and openWorldHint, so the safety profile is covered. The description adds that delivery can be inline or resource, but does not explain what that means for response size, resource handling, or error behavior. No contradiction with annotations.
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 sentence with the core action front-loaded and no filler. It is concise to the point of under-specification, but the structure itself is clean and easy to parse.
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?
Despite the helpful annotations and presence of an output schema, the tool has 8 parameters with zero schema descriptions. The description omits what the delivery modes actually control, the meaning of style/format, and how this tool relates to sibling map/tile tools. That is a significant completeness gap for correct invocation.
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 burden of explaining the 8 parameters. It partially does by framing x/y/z as ZXY tile coordinates and delivery as inline/resource, but style, format, and inlineMaxBytes are left undefined. Agents would have to infer most parameter meaning from names alone.
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 names a specific operation ('Fetch ... tile') and a specific resource ('raster ZXY tile'), which clearly identifies this as tile retrieval rather than map rendering or vector tile delivery. It is clear and accurate, though it does not explicitly differentiate among closely related map/tile sibling tools.
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?
No guidance is given for when to use this tool versus alternatives such as os_maps_render, os_vector_tiles_descriptor, or os_resources_get. The phrase 'inline/resource delivery controls' hints at a mode of operation, but no explicit when-to-use, prerequisites, or exclusions are provided.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.