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

The credit-consumption rule is the key behavioral fact and it is disclosed twice, including the edge cases (no contact, LinkedIn-only, already opened this month). Auth requirements and error/not-found behavior are not covered, and the readOnlyHint=false plus a billing side effect is left for the agent to reconcile.

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, both front-loaded with the highest-value information (what you get, then the optional paid expansion). The first sentence is a long semicolon-delimited list, which is dense but each item maps to a real returned section.

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?

There is no output schema, and the description compensates by enumerating the response sections, and the one costly parameter is fully explained. Nothing an agent needs to call this correctly 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?

Schema coverage is 100%, so the baseline is 3; the description earns a notch by stating what include_contacts actually adds to the response (published business contacts for the named people) and by framing the credit rule at the tool level rather than only per-field.

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 ("One firm from the Corridome register") and then enumerates the record's contents: identifiers, ADV funds, deals, relationships, portfolio companies, people. An agent can distinguish this single-firm detail fetch from search_firms without opening either schema.

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 conditional guidance on include_contacts (only when published contacts are needed, since each opened contact costs a credit). It never explicitly says to obtain firm_id from search_firms or when to prefer this over the sibling get_company/search_firms, so there is no named alternative.

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