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

Annotations only declare the safety profile (not read-only, not idempotent, not destructive), so the description carries the rest — and it does: pathfinding routes around walls/closed doors, pathCost (cells) signals multi-turn detours, Large+ tokens need wide corridors, and doorsOpened[] reports walls opened. Locked (ds=2)/secret (door=2) doors are called out as impassable with the remedy. This is far beyond what annotations convey.

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?

Front-loaded with the core action, then dense but information-bearing clauses separated by semicolons; every sentence is relevant. The single wall-of-text paragraph is heavy to parse, costing a point versus fully structured prose.

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 5-parameter mutation tool with no output schema, the description covers prerequisites, door/wall behavior, turn-cost interpretation, and the doorsOpened[] return value. Nothing essential to calling it correctly appears to be 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 coverage is 100%, so baseline is 3, but the description adds real meaning the schema lacks: the pixel = gridCoord * gridSize conversion for x/y and the doorsOpened[] side effect of canOpenDoors. tokenId sourcing is reinforced. It stops short of describing the animate parameter, but overall adds value over the schema.

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 and resource ('Move a token') plus the exact target semantics ('pixel coordinates (top-left corner; pixel = gridCoord * gridSize)'), which distinguishes it from token-update/list/delete without opening another schema. The coordinate convention alone tells an agent this is a positional move, not a generic field update.

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 concrete when/when-not guidance: tokenId comes from token-list, canOpenDoors should be used 'only when the user explicitly asks', and locked/secret doors require running scene-set-door-state first. It doesn't explicitly contrast against the sibling token-update, but the prerequisite and gating language is clear.

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