Hedge-fund / institutional position changes (SEC 13F, quarter-over-quarter)

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

Annotations already establish read-only, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds genuinely useful behavior beyond that: newest-first ordering, that ticker is deliberately left null rather than guessed, and a caveat that the delta is not a trading edge, plus a pointer to a per-response coverage note.

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?

Three dense sentences, front-loaded with the trigger, then filters, then row shape, then caveat. The row-field enumeration is long but justified because there is no output schema; nothing is pure filler.

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 usefully compensates by listing the returned row fields (as_of_quarter_end, filed_date, lag_days, value_usd, cusip, issuer_name, filing_url) and flagging the null ticker. It also scopes the data universe via the coverage note. Only the CIK/universe scope is deferred rather than stated, which is a minor 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 description coverage is 100%, so the schema already documents all six parameters in detail (including the limit<=0 no-cap rule and offset paging). The description only names four of them as filters and adds the 'newest first' ordering, which is not in the schema but is minor. Baseline 3 is correct here.

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 states a specific verb and resource (quarter-over-quarter SEC 13F position deltas) and enumerates the exact user phrasings that should trigger it ('what a fund bought or sold', 'opened/added/trimmed/exited a position'). This is precise enough to separate it from the verify_* siblings, which check a specific claim rather than surface deltas.

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 positive trigger conditions with concrete example questions, so an agent knows when to reach for it. It stops short of naming an alternative or an exclusion (e.g., when to prefer verify_13f_change), so it is context without routing.

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