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

There are no annotations, so the description carries the behavioral burden. It discloses that the call is free, read-oriented ('Returns'), and what the response covers (identity, prices, limits, custody, deletion rules, sunset, payment flow, error codes). It stops short of explicitly stating 'no side effects', but for a zero-parameter informational tool this is solid disclosure.

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?

Two short sentences, front-loaded with 'Free' and the core action, followed by a compact but complete list of contents. There is no filler, and each phrase earns its place.

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 discovery tool with no output schema, the description fully covers what the agent needs: when to call it, what it returns, and why it matters. The 'call first' guidance and detailed contents make the tool self-sufficient.

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?

With zero parameters, the parameter semantics burden is minimal; the baseline is 4. The description adds relevant context about what the returned contract contains, so no additional parameter explanation is 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 uses a specific verb ('Returns') and names a concrete resource ('the machine-readable contract') with an explicit inventory of contents. 'Call this first' also orients it as the discovery/meta tool, setting it apart from the operational locker_* siblings.

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 clear placement guidance with 'Call this first', which tells an agent when to use it relative to other tools. It does not explicitly list exclusions or alternatives, but the 'first' directive and complete contract framing make the intended usage clear.

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