Read this project's DESIGN.md

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

With no annotations, the description carries the behavioral burden and meets it: it labels the call as a 'cheap local read' and discloses the exists:false edge case. It could add error behavior or permissions, but for a non-mutating local read the disclosed traits are sufficient.

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 first sentence states purpose and output content; the second gives prioritized usage timing; the third covers the negative case. No sentence is wasted and the most important information is front-loaded.

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 description is complete enough for a one-parameter, read-only tool: it covers what the summary contains, when to use it, and the missing-file return. Because there is no output schema, a slightly more explicit success return shape would make it fully complete.

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 coverage is 100% and the only parameter, project_root, is fully explained in its schema description. The tool description adds no extra parameter semantics, so the baseline of 3 applies.

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 states a specific action (check for and summarize the project's DESIGN.md) and enumerates what the summary covers: originating design system, sections, and colour tokens. The 'current project' and 'local read' framing separates it from the sibling design-search tools.

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?

It gives explicit trigger conditions: before writing/editing frontend code, when resuming UI work, and before fixing visual bugs. It does not name an alternative sibling or state when not to use it, so it falls just short of full routing guidance.

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