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

Goes well beyond the annotations: it specifies the required Last Price credential with function read scope, the workspace-claim prerequisite with the concrete 403 failure mode for sandbox keys, and that setting values are never returned. With readOnlyHint already covering safety, this is meaningful added context; only the lack of any pagination/volume behavior keeps it from top marks.

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?

Front-loads the core purpose, then layers output shape, invocation caveat, and auth prerequisites. Each sentence carries distinct information, though the credential and workspace-claim sentences are dense and could be split or slightly trimmed.

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?

With no output schema, the description fully carries the burden: it enumerates returned fields and explains the negative states (adapters off vs. adapter unconfigured), plus auth scope and the 403 workspace-claim failure. An agent has everything needed to call this correctly and interpret the result.

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 takes zero parameters, so per the baseline this is a 4. The description adds no parameter-level detail, which is appropriate since none exist.

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?

States a specific verb (see which) and resource (outside pricing engines / vendor adapters), and names concrete examples (Pricefx, Prisync) plus the returned fields (function name, vendor, ready status). It implicitly separates itself from list_functions and routing by noting adapters are invoked by naming a function, but it does not explicitly name a sibling to disambiguate against.

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?

Explains the operational context: a ready adapter is used by naming its function in compute_price, never by automatic routing, which tells the agent what this listing is for and what it is not. There is no explicit 'when not to use' or alternative tool named, so it stops short of a 5.

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