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

Annotations already declare readOnly/openWorld/idempotent, but the description adds substantial behavioral context: fan-out to SEC EDGAR, GDELT→GNews fallback with a failure trigger ('rate-limited or 5xx'), USPTO soft-fail due to PatentsView API sunset, and a grouped changes return format with pipeworx:// citation URIs. This goes well 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 dense but efficiently organized: opening query patterns, then source fan-out details, then parameter behavior, then return value, then explicit alternative. Every sentence carries essential information, and the most actionable guidance is front-loaded. No filler or 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?

This is a multi-source, complex tool with no output schema, so the description must carry the burden of explaining behavior and returns. It covers the sources, fallback logic, failure modes, date formats, return structure, and the key sibling alternative. The description is fully sufficient for an agent to invoke this tool 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?

All three parameters are already fully described in the schema with the same examples (ISO date/relative shorthand, ticker/CIK, company-only enum). The description does not add meaning beyond the schema—it simply restates the same semantics in prose. Since schema coverage is 100%, a baseline of 3 is appropriate.

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 query patterns ('What's new with X' / 'latest on Y') then states its core function: 'change feed for a company in the last N days/weeks/months in ONE parallel call.' It names explicit output (changes[], total_changes, citation URIs) and differentiates from entity_profile by contrasting dynamic changes vs static profile.

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 gives clear when-to-use signals via natural-language examples and a time-window scoping ('in the last N days/weeks/months'). It also provides an explicit alternative: 'Use entity_profile instead when you want the static profile...' This directly guides tool selection and prevents misuse.

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