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

The readOnlyHint annotation already signals a safe read operation. The description adds meaningful behavioral context by explaining the tool computes all combinations with specific pass/fail grades and summary, and that it is a batch operation to avoid repeated calls. This goes beyond the annotation without contradicting it.

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 core purpose, and the second sentence gives a clear alternative. No extraneous information or repetition of schema details. Highly concise and well-structured.

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?

The tool has an output schema (not shown), so return values are already covered. The description fully explains the tool's role and provides context for when to use it, complementing the complete schema and readOnlyHint annotation. Nothing essential is 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 description coverage is 100%, with the palette parameter already described as an array of hex values with example and min/max constraints. The description only echoes 'palette array' without adding further nuance, so baseline 3 is appropriate.

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 clearly states the tool accepts a palette array and returns every foreground/background combination with contrast ratios, WCAG pass/fail grades, and a summary. It uses specific verbs and resource, and explicitly distinguishes itself from accessibility_check by noting it should be used instead of calling that tool multiple times.

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 'Use this instead of calling accessibility_check multiple times for a palette,' providing clear guidance on when to choose this tool over the named alternative. This is direct and actionable.

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