od_cost_matrix

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

With no annotations provided, the description carries the full burden. It discloses the license requirement, that it writes output to out_features within PathGuard allowed roots, and that it supports travel_mode and cutoff. Missing are details about overwrite behavior, potential side effects on input data, and the exact nature of the output lines.

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 three sentences, front-loaded with the core action, followed by use cases and then additional details. Each sentence serves a purpose, though it could be slightly more concise by combining the use case and detail sentences. Overall, it is well-structured and not overly verbose.

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's complexity with 7 parameters and the existence of an output schema, the description covers the essential purpose, prerequisite, and output behavior. It mentions PathGuard for output but not for other paths; however, the schema covers those. The description is sufficiently complete for an agent to understand when and how to use it.

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 input schema has detailed descriptions for all parameters, so baseline is 3. The tool description adds little beyond the schema, simply restating that travel_mode and cutoff are supported and that output goes to out_features. It does not add new meaning for individual parameters.

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 states 'Solve origin-destination travel cost lines' with a specific verb and resource, and provides multiple use case examples like measuring travel time between demand points and destinations. It clearly distinguishes its purpose from sibling network analysis tools like closest_facility or route_analysis.

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 explicitly says 'Use this to measure travel time or distance between demand points and destinations', giving clear guidance on when to use the tool. It also mentions the license requirement. However, it does not discuss when not to use it or suggest alternative tools among siblings.

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