Look at board

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

Annotations already declare readOnlyHint=true, destructiveHint=false, openWorldHint=false, so safety is covered. The description adds value beyond that by disclosing the mechanism (headless browser render) and, critically, the return payload (PNG plus per-item measured boxes plus layout warnings) — necessary since there is no output schema. It omits cost/latency expectations for a rendering call, which would be the remaining useful detail.

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, no filler, with the core behavior and the return shape front-loaded before the usage advice. Every clause carries information an agent needs.

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 four optional params, a nested region object, and no output schema, the description does the important work of explaining what comes back and when to invoke it. Missing only secondary context such as render cost or what a 'layout warning' severity implies.

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% (width, region, chapter, overview all documented in-schema, including the nested region fields), so the baseline is 3. The description adds no parameter-level guidance such as when to prefer overview over chapter, or how region interacts with the default camera view.

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 ('Render the board in a headless browser') and enumerates the outputs: PNG as the learner sees it, measured boxes per item, and layout warnings. That is clearly distinct from board_read (data) and board_update (mutation), and the second sentence names board_update explicitly.

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?

'Use it after significant changes, then fix problems with board_update' gives both a timing trigger and the correct follow-up tool. No explicit when-not-to-use case (e.g., don't call for pure data reads), so it falls short of a full 5.

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