OpenStreetMap MCP Server

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

With no annotations provided, the description carries full burden but provides minimal behavioral information. It mentions the technology (Valhalla) but doesn't disclose rate limits, authentication requirements, computational cost, output format, or error conditions. For a complex geospatial calculation tool, this leaves significant gaps in understanding how the tool behaves beyond basic functionality.

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 a single, efficient sentence that packs essential information: action, definition, and technology. Every word earns its place with no redundancy or unnecessary elaboration. It's perfectly front-loaded with the core functionality.

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 tool with 6 parameters, no annotations, and no output schema, the description provides adequate basic purpose but lacks important contextual information. It doesn't explain what the output looks like (geojson? image?), performance characteristics, or common use cases. The schema handles parameter documentation well, but the description should compensate more for the missing annotations and output schema.

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?

The description doesn't add parameter details beyond what's already in the schema (which has 100% coverage), but it provides crucial context by defining what an isochrone is and mentioning Valhalla. This helps the agent understand the overall purpose of the parameters. Since schema coverage is complete, the baseline is 3, and the additional context justifies a 4.

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 specific action ('calculate travel time isochrone'), defines what an isochrone is ('areas reachable within time limit'), and specifies the technology used ('using Valhalla'). It distinguishes itself from siblings like 'get_distance_matrix' or 'get_osrm_route' by focusing on area-based reachability rather than point-to-point routing or distance calculations.

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 through the term 'isochrone' and Valhalla reference, suggesting it's for geographic accessibility analysis. However, it doesn't explicitly state when to use this tool versus alternatives like 'get_distance_matrix' for multiple point-to-point calculations or 'get_osrm_route' for specific route planning. No exclusions or prerequisites are mentioned.

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