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

Despite no annotations being provided, the description fully discloses behavior: it notes 'Free, no side effects,' explains that renamed functions change mcp_name but keep tool_id, and details the registered:false/unregistered semantics for deployment drift detection. It even references issue numbers (#174, #175) for context. This is rich behavioral disclosure that carries the entire burden absent 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 well-structured with clear paragraphs covering purpose, consumers, canonical-UUID design, and wire-surface diffing, ending with 'Free, no side effects.' It's slightly verbose with some redundancy ('flag deploy drift' appears twice, the canonical-UUID point is reiterated), but each sentence earns its place and there's no fluff.

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 zero-parameter tool with an output schema present, the description is thorough. It explains the return structure (registered flags, unregistered array), the semantics of tool_id stability across renames, and the drift-detection value. Given no params to document and an output schema exists, the description fully covers what an agent needs to use this correctly.

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 and 100% schema coverage (effectively empty schema, nothing to document). With 0 params, the baseline is 4. The description adds value by explaining what the output contains (registered:false, unregistered array) which orients expectations even though no parameter semantics are needed.

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 returns canonical (tool_id, mcp_name, ...) for every exposed tool, which is a specific verb+resource+deliverable. It distinguishes itself from siblings by directly positioning it as the authoritative source for identity resolution, unlike list_coupons, list_posts, etc. which list domain data.

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 names concrete consumers ('Studio, agents, FE') and specific use cases ('Reconcile uses this output to UUID-join against the stored pricing model'). It explicitly states when NOT to use it ('no name-based UUID derivation, no guessing') and explains what the authoritative-canonical design solves. This gives an agent clear decision context for when this tool is the appropriate choice.

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