13F Holder Mix

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

Annotations already establish readOnlyHint=true, and the description adds genuine behavioral context beyond that: results are anonymized aggregates by filer type, and the active-holder change deliberately excludes index-like books. That tells the agent what the numbers mean and what they omit, which annotations cannot 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?

The output scope is front-loaded, but the two long sentences are dense and run-on, packing dimensions and the index-exclusion caveat together. It is informative yet heavier than needed for three parameters.

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 explain return values and does so well: bucket share, like-for-like change, and new/exited filer counts, plus the active-holder variant. Only the routing against sibling holder tools is left implicit.

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% and the dimension parameter already lists its allowed values, so the schema carries the parameter burden. The description restates the dimension options and clarifies they are holder-splits rather than adding new semantics, so the baseline 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?

States a specific resource (13F holder mix for a stock/ETF) and the concrete outputs: each bucket's share of 13F common shares, like-for-like change, and new/exited filers. The 'regulatory records, never names' clause distinguishes it from name-level siblings like GetTopHolders, though it never names an alternative outright.

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 'never names' note suggests this is the aggregate view versus a name-level tool, but there is no explicit when-to-use or when-to-prefer-a-sibling statement despite many overlapping neighbors (GetTopHolders, GetHolderTypeFlows, GetMostHeldStocks).

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