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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety is covered by structured data. The description adds only that one record is returned; it says nothing about behavior when the slug is unknown, whether the lookup is cached, or what a miss looks like. Minimal added value beyond 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?

A single six-word sentence with no filler and the identifying key front-loaded. It is efficient, though so terse that it leaves the usage gap noted above.

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?

An output schema exists, so return values need not be described, and annotations cover the safety profile. For a one-parameter detail tool this is close to adequate, but the absence of any sibling routing or slug-sourcing guidance leaves a real gap.

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 coverage is 100% and the single slug parameter is documented with an example (gumroad) directly in the schema, so the description's 'by slug' wording is redundant. Baseline 3 is appropriate when the schema fully documents the parameters.

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 names a specific resource (TrustMRR dataset startup record) and its access key (by slug), which cleanly separates it from the list-oriented sibling datasets_trustmrr_search and the time-series datasets_trustmrr_history. It does not name those siblings explicitly, but the 'record by slug' framing is enough for an agent to distinguish a single-item fetch.

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 statement of when to use this tool versus datasets_trustmrr_search, _facets, or _history, nor any mention that a slug must first be obtained from search. The 'by slug' phrase implies a detail lookup, but the agent must infer the workflow entirely.

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