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

With only readOnlyHint=true in the annotations, the description carries rich extra context: inclusion thresholds (|mark_delta| >= 1.0 point, fair value >= $500k), how implausible moves are diverted to `suspect_moves`, what `coverage` reports, ticker/limit caps, and the SEC 10-K/10-Q source. This is well beyond anything the annotations convey.

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?

Purpose and the answering question are front-loaded, and the dense sentences each carry substantive rules (thresholds, caps, output keys). It is information-rich rather than padded, though the packed run-on style slightly reduces skimmability.

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, yet the description enumerates the return shape ({increases, decreases}, row fields) and the auxiliary fields (suspect_moves, coverage). For a two-parameter read-only query tool, everything needed to call and interpret it correctly is present.

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 both parameters are already documented, including the caps and the GLOBAL-ranking note. The description largely restates those facts (capped at 25, limit default 10 / hard 50 per direction) rather than adding syntax or format meaning, so the baseline 3 holds.

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 — quarter-over-quarter mark moves across a set of BDC portfolios — and frames it with the exact question it answers ('which borrowers got marked up or down the most last quarter, and by whom'). This is clearly distinguishable from siblings such as ol_bdc_credit_quality or ol_bdc_borrower_dispersion 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?

The quoted question supplies an implied use case, and 'in ONE deterministic call' hints at it being the consolidated option, but the description never names alternatives or when NOT to use it. Usage context is present but alternatives are left to inference against a large BDC sibling set.

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