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

Annotations already indicate read-only, idempotent, non-destructive, but the description adds substantive behavioral context: it is public, requires no token, returns a specific JSON shape, and references the underlying document '/.well-known/comos-vendor.json'. The explicit statement 'This tool changes nothing' reinforces the read-only nature beyond the annotation booleans.

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 dense but well-structured: it leads with purpose, then return value, then application steps, then exact return shape, then an example. Each sentence adds distinct value with minimal redundancy. Slightly long but efficient for the information conveyed.

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 no output schema, the description fully compensates by detailing the return object structure ('{ offer: ..., how_to_apply: { step_1, step_2, note } }'), pricing tiers, auth requirements, and the relationship to the well-known document. The tool is simple and the description leaves no important behavior unexplained.

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 description coverage is 100% for the single optional 'channel' parameter, so the schema already provides full semantics. The description does not discuss the parameter, but it does include an example 'call federation_offer with arguments {}', which hints that no parameters are needed. This is baseline 3 as the schema carries the parameter detail.

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 opens with a specific verb+resource: 'Read the ComOS network's vendor offer', clearly stating what the tool does. It further differentiates from siblings by declaring it 'public and read-only, no token needed' and explicitly contrasts it with federation_apply ('this tool changes nothing; it is the door's window, and federation_apply is the door').

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: read the offer first, then apply via federation_apply. It states 'then call federation_apply with it', naming the alternative and giving a clear sequence. It also notes the tool requires no token, so the agent knows when it can be invoked without auth.

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