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

Annotations already establish readOnlyHint=true and openWorldHint=false, so the safety profile is covered; the description adds substantive data-scope behavior instead. It discloses the recency cutoff (2 years), the 1% minimum, the exclusion of foreign and minority-shareholder aggregates, and that each row carries as_of and source_url. It does not address error behavior or empty-result handling, so it is strong but not exhaustive.

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?

The core resource and aggregation rule are front-loaded, followed by data-coverage caveats and per-row fields, with no filler sentences. Density is high but each sentence contributes scope or output information. The mid-sentence source=major/insider clause is the one spot that reads ambiguously against a schema with only ticker.

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 must convey return shape, and it does: holder-level rows with ownership ratio, as_of, and source_url. Combined with the exclusion rules, an agent knows what will and will not appear. Remaining gaps are edge cases (empty results, ticker ambiguity) rather than core behavior.

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?

There is a single required parameter (ticker), and schema description coverage is 100% (ticker code or exact name), so the schema already carries the semantics. The description adds nothing about ticker resolution behavior and instead discusses source names that are not parameters, so the baseline of 3 applies.

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+resource: major holders and their ownership percentages for a stock, with special related parties aggregated. It clearly bounds what counts as a holder (5% bulk-holding reports, insiders incl. 10%+ shareholders, 1%+ threshold). It does not explicitly distinguish itself from siblings like get_holder_history or search_holder, which keeps it from a 5.

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 implied through scope statements (latest disclosure per holder, holders without reports in the last 2 years excluded, no foreign/minority totals), which signals when results will be thin. However, there is no explicit when-to-use/when-not guidance and no named alternative such as get_holder_history for time-series needs. The mention of source=major/insider is not a selectable parameter here, which adds mild ambiguity about how to choose coverage.

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