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

Annotations already declare this as read-only and non-destructive. The description adds behavioral context by explaining that `skill_name` is an 'opaque registry ID' that must be copied verbatim, and warns against fabrication. It also discloses the return behavior (SKILL.md or specific file). This goes beyond the structured annotations.

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 two sentences with no wasted words. It front-loads the purpose and then provides a critical usage instruction. Every sentence earns its place.

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 the tool's simplicity (2 params, no output schema), the description is complete: it explains what is returned, the prerequisite step (search_documentation), and the need for exact input. The annotations cover safety aspects, so no additional behavioral disclosures are required.

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 baseline is 3. The description reinforces the need to copy `skill_name` verbatim and avoid guessing, but the schema already contains these details. The description adds minimal parameter-specific meaning beyond what the schema provides, so it stays at baseline.

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's purpose: 'Retrieve an AWS skill (workflows, references). Returns SKILL.md, or `file` if given.' It specifies the resource (AWS skill) and the output behavior, and distinguishes itself from siblings by referencing the search_documentation workflow and the skill_name registry ID.

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 provides explicit when-to-use guidance: 'Call `search_documentation` FIRST and copy `skill_name` verbatim.' It also warns against guessing inputs. However, it does not explicitly mention alternatives or when not to use this tool, so it stops short of a perfect score.

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