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

Annotations already declare readOnlyHint=true and destructiveHint=false, and the description reinforces this with 'Read-only' while adding useful cost context ('about 93 credits ~$0.093 per call'). It also clarifies the tool only critiques and does not rewrite, which is meaningful beyond the schema and annotations. It does not disclose the exact output structure, but the annotation safety profile lowers the burden.

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?

The description is compact and front-loaded: the first sentence states what it does and what it returns, the second prevents misuse, and the cost line is a genuinely useful decision signal. Every sentence earns its place with no filler or repetition of the schema.

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 read-only review tool with no output schema, the description gives enough context to select and invoke it correctly: expected input type, return categories, non-rewriting behavior, the sibling to use for fixes, and cost. An agent would understand what this tool is for and how it differs from siblings like revision and humanize.

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 the schema already explains letterText, focus, and purpose. The description adds no parameter-specific syntax or formatting details beyond what the schema provides. The baseline of 3 applies because the schema carries the burden 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?

The description names a specific verb ('Analyze') and resource ('finished recommendation letter') and states the tool's output with concrete categories: vague, asserted without evidence, generated. It also distinguishes itself from rewriting via 'not to rewrite one' and points to 'revision' as the sibling that applies fixes.

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 when to use it ('critique a draft') and when not to ('not to rewrite one'), and names the alternative tool to use for applying fixes ('use revision'). It also adds an economic signal ('far cheaper than drafting'), which helps the agent choose appropriately.

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