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

Annotations already establish readOnly/idempotent/non-destructive/closed-world, so the safety profile is covered. Beyond that the description discloses genuinely useful behavior: asymmetric naming coverage across sides, the ambiguity of a public-side exit, that `by_bucket` aggregates by investor type rather than category totals, and that meta.available_quarters enumerates stored quarters — non-obvious traits an agent would otherwise misread.

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?

Leads with the core verb-plus-scope sentence, then layers the aggregation, quarter-availability, and coverage caveats in descending order of importance. Dense but nearly every clause carries disambiguating information; the by_bucket and meta clauses are slightly implementation-flavored but still earn their 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?

For a read-only lookup with no output schema, the description covers the fields returned (shares, % held, pledged/locked, investor_type, stable investor_id), the aggregate block, the meta block, and the coverage caveat that governs interpretation. An agent has everything needed to call it and to correctly read the result.

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% with enum values for `side` and `investor_type`, so all six parameters are fully documented structurally. The description adds little parameter-specific meaning beyond the investor_type grouping implied by `by_bucket`, which is the expected baseline when the schema carries the load.

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 with precise scope: 'List the NAMED shareholders of a stock for one quarter', then enumerates exactly which holders qualify (promoter-group entities plus public holders at 1%+). The scope definition implicitly separates it from a broad shareholding tool, but it never names a sibling such as get_shareholding or get_named_holder_history, so differentiation is left to inference.

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?

Gives real interpretive guidance — a public-side 'exit' can mean the holder dropped below the 1% threshold rather than sold, via listed_from/listed_to — which tells an agent how to read results. However there is no explicit when-to-use/when-not statement and no named alternative for time-series (get_named_holder_history) or deltas (get_named_holder_changes), so choice between siblings is only implied.

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