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

Annotations already declare readOnly, idempotent, non-destructive, so the safety profile is covered. The description adds real value beyond that: the ranking methodology, the SEC-filing source of truth, and the pagination-per-lender behavior ('a page per lender').

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 dense sentences with the purpose front-loaded and zero filler. The first sentence is information-heavy but every clause (ranking, window, source) 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?

With no output schema, the description compensates by enumerating return fields (volume, loan count, size range, median rate, leverage). For a 4-param read-only filter tool this is nearly complete, though default limit behavior is left to the schema.

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 above that by clarifying the non-obvious semantics of loan_amount as a spanning filter rather than an exact match, and by signaling that property_type/state are optional limiters.

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 and resource ('CMBS originators ranked by loan volume') plus the data provenance (originator named in trusts' SEC filings) and time window. An agent can clearly distinguish this ranked-list tool from the singular get_cmbs_lender sibling without opening a 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?

Explains what each filter does, including the subtle 'keeps lenders whose securitized loan sizes span it' semantics for loan_amount, which tells the agent when that filter is appropriate. It stops short of explicitly routing between siblings like get_cmbs_lender or size_cmbs_loan, but the usage context is clear.

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