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

Beyond the readOnly/openWorld/idempotent annotations, the description discloses multi-source fan-out to SEC EDGAR, GDELT/GNews fallback with specific trigger conditions (rate-limited or 5xx), the PatentsView API sunset causing soft-fail, and the return shape (changes[] grouped by source, total_changes count, citation URIs). This is rich behavioral context with no contradiction.

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 long but every clause earns its place: intents, source logic, fallback behavior, parameter formats, output summary, and the alternative tool. It is front-loaded with user-facing natural language examples and remains dense without redundancy.

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 complex multi-source tool with no output schema, the description covers all necessary aspects: usage, parameters, source behavior, limitations (patent sunset), output structure, and alternatives. The agent has enough to invoke correctly and interpret results.

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%, so the baseline is 3. The description reiterates the `since` format and value examples but adds no new parameter semantics beyond what the schema already provides (e.g., the '30d' typical-monitoring advice is already in the schema). It remains at baseline.

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 opens with concrete user intents ('What's new with X', 'latest on Y'), then defines the tool as a 'change feed for a company in the last N days/weeks/months'. This is a specific verb+resource+scope. It also explicitly distinguishes itself from entity_profile by directing static-profile queries there, which separates it from the closest sibling.

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?

It clearly states when to use this tool: for temporal change-feed queries ('what's new', 'updates'). It explicitly names an alternative, entity_profile, and explains the difference ('static profile ... regardless of window'). This meets the 5 standard for explicit when-to-use and when-not-to-use.

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