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

Annotations already declare this is a non-destructive, non-idempotent write, so the safety profile is covered. The description adds useful behavior with 'auto-detect' for input/inputs, but omits that repeated calls create duplicates (non-idempotent), any auth requirements, and the 30-item cap that lives in the schema.

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 sentences, front-loaded with the action and the legal argument shapes, no filler. Every clause maps to a distinct calling mode.

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 6-parameter, nested-object mutation with no output schema, the description covers the central ambiguity an agent faces (what to pass for the content). Gaps remain around size/color defaults and duplicate behavior on repeat calls, but nothing blocks a correct invocation.

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?

With 67% schema coverage, the description's main contribution is disambiguating the mutually exclusive input paths: `inputs` for a batch, `input` for a single value, `tile` for a raw object. It doesn't touch size, color, or after, but the enums and existing schema text carry those adequately.

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 ('Add tiles') that sits clearly against the update_tile/move_tile/remove_tile siblings. It doesn't explicitly name an alternative, but the add-vs-modify distinction is unambiguous from the name and first sentence.

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 explains the three input modes (inputs for several, input for one, tile for full object), which is implied usage guidance for how to call it. It gives no explicit when-to-use or when-not-to-use against siblings like update_tile or import_page, so the agent must infer.

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