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

Annotations already declare read-only, idempotent, and non-destructive behaviors. The description adds substantial context beyond annotations: the return object's field names, the caveat about door-state ('open via tokened apply; tokenless never admits'), and the note that the thesis is 'relayable verbatim to the human root.' No contradictions exist.

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 overlong and contains redundancy, notably repeating 'Returns' twice and listing the thesis fields twice in slightly different words. It is front-loaded with the core purpose, but the verbose marketing-style language could be trimmed. It would benefit from a more concise structure.

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 informational tool with no output schema, the description fully covers what the tool does, what the response contains (thesis object fields), the caveat, and pointers to related tools. It gives the agent enough context to know when and why to call it, and what to expect in return.

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 the description explicitly confirms this with 'Example: call federation_why with arguments {}.' It also explains what the returned thesis object contains, giving meaning to the call even though no parameters exist. Baseline for 0 params is 4, and the description adds further clarity, justifying a 5.

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: 'Why build on ComOS — the case for becoming a vendor, not just a buyer.' It explicitly contrasts with federation_help ('tells you HOW; this tells you WHY'), distinguishing it from the closest sibling. The verb 'returns the thesis' and detailed content further specify the resource.

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?

Provides explicit usage guidance: 'Read this if you (or your human) are deciding whether to invest a few Coms to stand up a business.' It also names the alternative (federation_help) and explains the choice. This tells the agent exactly when to invoke this tool versus others.

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