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

With no annotations, the description carries the full burden. It discloses the return fields, notes the tool is cheap to call, and explains edge-case behavior: 'If gitSha is "unknown" or indexedAt is far in the past, surface that to the user before relying on the data.' This goes beyond basic functionality and provides actionable behavioral guidance.

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 three sentences, each earning its place: what it returns, when to call it, and how to handle stale data. It is concise, front-loaded, and free of any filler.

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 (zero params, no output schema), the description covers all necessary context: return fields, usage timing, cost, and edge-case handling. It is complete for an agent to use the tool correctly without further clarification.

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 tool has zero parameters, so the baseline is 4. The description does not need to add parameter semantics; it focuses on return values and usage. Since schema coverage is 100% (vacuously), this score 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's purpose: 'Returns the MCP knowledge version' with specific fields listed (gitSha, indexedAt, componentCount, patternCount, uptimeSeconds). This is a specific verb+resource and is distinct from sibling tools like get_component_info or get_design_guidelines.

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 usage context: 'Call this ONCE per session before generating UI code so you know how fresh the design-system data is.' This tells the agent when to use it, though it does not explicitly mention alternatives or when not to use it. The 'Cheap to call' note further clarifies it is safe to invoke frequently.

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