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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the description does not need to repeat these. It adds valuable context by stating 'Requires FolioFact Pro' (an access restriction) and specifying 'Form 4/5' (the exact regulatory filing type). This goes beyond the structured fields without contradicting them, earning a 4.

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 short sentences: 'Recent Form 4/5 insider transactions for one company. Requires FolioFact Pro.' Every piece of information (content type, scope, access requirement) earns its place. It is front-loaded and free of any irrelevant detail, making it highly concise and well-structured.

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?

Given the tool's simplicity (one parameter, output schema present, annotations cover safety), the description is largely complete. It states the data type (Form 4/5), the granularity (one company), and a key prerequisite (Pro subscription). Minor details like how 'recent' is defined or pagination are not mentioned, but the output schema likely covers return structure. Overall, it provides sufficient context for a straightforward tool.

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 input schema provides 100% coverage for the single parameter 'ticker' with a description ('Stock ticker (dots allowed).'). The description adds no additional parameter semantics or examples. With full schema coverage, the baseline is 3, and there is nothing extra to justify a higher score.

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's function: 'Recent Form 4/5 insider transactions for one company.' It uses a specific verb ('transactions') and resource ('insider transactions'), and explicitly limits scope to 'one company,' distinguishing it from broader tools like insider_feed. This is a precise and unambiguous purpose statement.

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 implies usage context (single company vs. a feed) but does not explicitly mention alternatives or when not to use this tool. The phrase 'for one company' suggests it is for a single ticker, but no exclusions or sibling tool comparisons are provided. This is clear context without explicit guidance, so a 3 is appropriate.

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