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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false. The description goes beyond annotations by adding operational details: parallel fan-out to three sources, fallback triggers (rate-limited or 5xx), USPTO sunset soft-fail behavior, and the structured return shape with citation URIs. No contradiction exists.

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 and front-loaded, but the opening list of query paraphrases ('What's new with X' / 'latest on Y' / etc.) is somewhat repetitive. However, every subsequent clause adds necessary information: source fan-out, fallback, sunset, since formats, return shape, and alternative tool. It's well-structured and appropriately sized for a tool with this complexity, though not maximally concise.

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 medium-high complexity (multi-source, fallbacks, soft-fail, no output schema), the description covers all essential aspects: return structure (changes[] grouped by source + total_changes + citation URIs), source priority and failure modes, date formats, and the key sibling alternative. Combined with the rich annotations, the agent has enough context to invoke the tool correctly without needing an output schema.

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 coverage is 100%: all three parameters have descriptions (type only company, value ticker/CIK, since types and examples). The description adds extra semantic value by explaining since accepts both ISO dates and relative shorthand with examples ('7d', '30d', '3m', '1y') and recommending '30d' or '1m' for typical monitoring—practical guidance beyond the schema. This warrants a score above the baseline 3.

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 is front-loaded with concrete query phrasings ('What's new with X', 'latest on Y') and then defines the tool as a 'change feed for a company in the last N days/weeks/months in ONE parallel call,' listing the exact sources (SEC EDGAR, GDELT/GNews, USPTO). It explicitly distinguishes itself from entity_profile by pointing to the alternative for static profiles, so the purpose is clear and scoped.

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 explicitly says 'Use entity_profile instead when you want the static profile ... regardless of window,' providing a clear when-not-to-use. It also gives typical window guidance ('Use "30d" or "1m" for typical monitoring') and explains source fallback behavior (GDELT preferred, GNews when rate-limited/5xx, USPTO soft-fails). This tells the agent exactly when and how to use the tool.

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