Find a path around walls

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds valuable behavioral context: it computes a path and its length, does not move anything, and works without a drawn canvas. It could mention whether the path is returned as a list of points or cells, but the description adds meaningful behavior beyond the 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?

Three sentences, each earning its place: the core function, the non-mutation clarification, and the no-canvas prerequisite. The most important scoping information is front-loaded. No wasted words.

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 pathfinding tool with 100% schema coverage and no output schema, the description is nearly complete. It covers the core inputs, the wall-type variants, the non-mutation guarantee, and the canvas prerequisite. A minor gap is that it doesn't describe the return format (e.g., list of points, length), but the description already states it returns the path and its length, which is sufficient for an agent to invoke it 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 schema already documents all five parameters. The description adds the 'type' enum semantics ('Which walls count') and the 'maxCells' search limit concept, but it doesn't add much beyond the schema. Baseline 3 is appropriate because the schema carries the parameter documentation burden.

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 a specific verb ('Find a way'), a resource ('from a token or point to another'), and the key constraint ('around walls that block movement (or sight, light, sound)'). It also distinguishes itself from the sibling 'move-token' by explicitly saying 'Moves nothing; move-token moves a token.' This makes the tool's purpose unmistakable.

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 when to use this tool ('Find a way... around walls') and contrasts it with the alternative ('move-token moves a token'). It also notes that it 'Works without a drawn canvas,' which clarifies a common prerequisite. This is strong usage guidance.

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