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

Annotations already declare readOnlyHint=false and openWorldHint=true, so the agent knows this is a world-mutating operation. The description adds genuinely non-obvious information the annotations don't carry — that long trips can terminate early with partial=true and are resumable. It still doesn't say what happens when no path exists, whether blocks are broken, or how long a call may block.

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?

Two short sentences, no filler, and the core action leads. The partial=true caveat is placed immediately after so it is read before invocation.

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?

With a 5-parameter schema, full coverage, and no output schema, the description does the minimum: it explains the one field the agent will actually receive (partial) and the follow-up call. It leaves open the failure mode when no reachable path exists and whether the agent can land in danger en route.

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 every parameter — including y's 'omit to use surface height' and range's stop-within semantics — is already documented. The description adds no parameter meaning beyond the schema, so the baseline 3 applies.

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 ('Pathfind to a point') and names the algorithm (A*), which tells an agent this computes a path rather than performing an instantaneous teleport. It doesn't explicitly contrast with the sibling 'move', so an agent must infer that 'move' is the short-hop/step variant.

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 second sentence gives real operational guidance: if the result comes back partial=true, call again to continue. That covers the retry case, but there is no statement of when to prefer this over 'move' or 'attack', nor any prerequisite or failure condition to watch for.

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