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

Annotations already cover safety (readOnly, idempotent, closed-world), and the description adds real behavior on top: conditional disclosure rules ('special servicer is named only when one trust holds the whole loan and its report names one') and entitlement gating (Pro/Team keys unlock extra fields). It does not say what happens if the slug is unknown or whether null fields are omitted.

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, front-loaded with the returned payload and followed by the tier-gated additions. Dense but every clause names a distinct data element; only slight cost is that the field list reads as a run-on with no grouping.

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, so the description must carry the return contract, and it does so exhaustively including conditional fields and tier-based availability. For a single-parameter read tool this is as complete as an agent needs to decide and call correctly.

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 slug parameter is already documented as 'the last part of its cmbs.news URL, from search_loans', so the description adds no parameter meaning. Baseline 3 applies since the schema carries the param semantics fully.

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 enumerates exactly what a single-loan lookup returns: terms, status, coverage, occupancy, three largest tenants, watch flags, trust holdings, trustee-report facts. That enumeration plus the 'One loan' scope cleanly separates it from search_loans (discovery), get_loan_history, get_loan_parties, and get_trust.

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?

Usage is only implied: the promise that 'A Pro or Team key adds the 12-month history' hints this is the aggregate view rather than the history endpoint, but the description never states when to call this vs get_loan_history or get_loan_parties, nor any prerequisite such as obtaining the slug from search_loans.

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