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

Annotations already cover the safety profile (readOnly, openWorld, idempotent, non-destructive). The description adds meaningful behavioral context: the data comes from the 'live Trust API' and is 'coverage metadata only', explicitly stating it is not an endorsement or approval. This helps the agent interpret the data appropriately beyond the 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?

Two sentences with no fluff. The first sentence front-loads the core function and outputs; the second adds a crucial caveat about the data's nature. Every clause earns its place, and the structure is immediately scannable.

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 simple, zero-parameter, read-only listing tool with no output schema, the description fully covers what is returned (fields), the source (live Trust API), and the intended interpretation (coverage metadata). Nothing an agent needs to call it correctly or interpret the result is missing.

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, and the schema has no properties. Per the rubric, a zero-parameter tool gets a baseline of 4. The description adds no parameter details because none are needed, and the schema coverage is effectively 100%.

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 states a specific verb ('List'), a precise resource ('every Lodestar Stamp market'), and enumerates the returned fields (slug, name, identity, receipt fields, business count, edition). It clearly distinguishes this from sibling tools that handle receipts, businesses, gaps, indices, or sources, so an agent can tell them apart without opening schemas.

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?

There is no guidance on when to choose this tool over the sibling list tools (list_gaps, list_index, list_sources). The description clarifies what the data is not (comparison/endorsement) but does not specify when a market listing is needed versus other listing types. No alternatives are mentioned, leaving the routing decision to inference.

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