match_track_selection

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

Annotations already cover the read-only/idempotent safety profile, and the description adds substantial context beyond them: the external Valhalla dependency, the OSM_VALHALLA_URL configuration requirement, the no-OAuth/loopback privacy behavior, and the critical epistemic constraint that 'routing results are diagnostic only, not evidence for OSM geometry.' No contradiction with the readOnlyHint.

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?

Four dense sentences (~65 words) with the core action front-loaded. Every sentence earns its place: what it does, how to configure it, privacy/network trait, workflow optionality, and output trustworthiness. No filler.

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?

Complete for invocation: external dependency and config are documented, optionality is explicit, and an output schema exists so return values don't need description coverage. Minor gaps are costing semantics and behavior when Valhalla is unavailable, but nothing an agent needs to call it safely is missing.

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 compensate. The phrase 'GPX selection' clarifies selection_id's referent and 'Valhalla service' gives domain context for the costing parameter, but neither parameter is explicitly explained and valid costing values (auto, bicycle, pedestrian, etc.) are not hinted at.

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 verb+resource: 'map-match a GPX selection' using a named service (Valhalla). It distinguishes itself from the pipeline siblings by positioning itself as the optional routing/diagnostic step before suggest_track_road_candidates and preview, so an agent can tell it apart without opening schemas.

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 clear workflow context: the step is 'optionally' required and 'can be skipped before suggest_track_road_candidates and preview', and it names the downstream siblings. It doesn't spell out explicit when-to-use conditions or block-list alternatives, but the optionality note is actionable guidance.

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