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

Annotations already indicate readOnlyHint=true and destructiveHint=false. The description goes beyond this by stating it returns current and prior quarter filing pairs with delta summary scaffolding, mentions the source (SEC EDGAR), the required identifier (ticker or cik), and the cost ($0.50 USDC). These are meaningful behavioral details that help the agent understand what to expect, adding value beyond the annotations.

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 description is two sentences, front-loading the purpose first, then detailing output, source, requirements, and cost. Every sentence provides necessary information without redundant phrasing. It is compact and efficient, with no wasted words.

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 tool with no output schema, the description explains what the agent receives: 'current and prior quarter filing pairs with delta summary scaffolding.' It also notes the source and identifier requirement. While the phrase 'delta summary scaffolding' is somewhat vague, it gives a sense of the output structure. Given the simplicity of the tool and the read-only nature covered by annotations, this is reasonably complete, though it could mention specific fields or limitations.

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?

The schema has two parameters (cik, ticker) with no descriptions in the schema (schema_description_coverage=0%). The description states 'Requires ticker or cik,' which clarifies that at least one is needed, but does not explain the distinction, format, or behavior if both are provided. It adds essential guidance but leaves some ambiguity about the relationship between the two params. This is adequate but not comprehensive, given that the description must compensate for the lack of schema descriptions.

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 clearly states the tool retrieves institutional 13F-HR holdings changes between quarters, with a specific verb ('get') and resource (13F-HR holdings delta). It explicitly mentions the use case (QoQ holdings change context) and distinguishes from siblings like get_sec_insider_trading by the unique focus on 13F filings. The purpose is unambiguous and specific.

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 description provides an explicit when-to-use scenario: 'Use when comparing institutional 13F-HR filing quarters for QoQ holdings change context.' It clearly defines the condition under which this tool is appropriate. It does not explicitly mention alternatives or exclusions, but the context is specific enough to guide selection among the many sibling tools. Given the clarity, a 4 is appropriate.

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