Get a foundation document

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

Annotations already declare readOnlyHint=true, so the description does not need to restate safety. The description adds context about the tool's purpose ('reasoning behind the system') and usage timing, but does not disclose return format, pagination, or other behavioral traits. This is adequate but not rich beyond what annotations convey.

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, front-loading the content scope and then adding a clear usage instruction. The list of topics is somewhat long but directly reflects the valid parameter values, so it is informative rather than redundant. No filler or unnecessary wording.

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 simple read-only tool with a single enum parameter and no output schema, the description covers the essential context: what the document contains and when to read it. It does not explain the return structure, but that is unnecessary given the tool's simplicity and the readOnlyHint annotation. Complete enough for reliable selection and 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?

The input schema provides 100% coverage with a descriptive enum list and a 'Foundation id.' description. The tool description repeats the enum values in prose, which adds context but no new semantic meaning about parameter usage. The baseline of 3 applies when the schema handles parameter documentation well.

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 retrieves a foundation document covering design system reasoning, listing specific areas like principles, color, and typography. This distinguishes it from sibling tools like get_tokens or get_component, which fetch different resource types. The verb 'get' plus resource type and content scope make the purpose explicit.

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 instruction 'Read the relevant foundation before implementing in that area' provides clear guidance on when to use this tool: as a prerequisite for implementation work. It does not explicitly name alternatives or exclusions, but the context is strong enough to avoid misuse. A 5 would require explicit when-not-to-use or alternative tool references.

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