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

Beyond the readOnly/idempotent annotations, the description discloses the tool's fan-out to multiple APIs, the fallback chain, and the USPTO soft-fail due to PatentsView sunset. This significantly enriches the behavioral model for an agent, especially since no output schema 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?

Despite being dense, the description is efficiently structured: it opens with example queries, then lists sources and fallbacks, parameter formats, return structure, and ends with the alternative tool. Every sentence carries operational value; no fluff or repetition.

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 complexity (multi-source, fallbacks, parameter variants) and the absence of an output schema, the description fully covers return values (changes[] grouped by source, total_changes, citation URIs) and source behavior. It leaves no critical ambiguity for an agent to resolve.

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%, so the baseline is 3. The description adds a practical recommendation ('Use 30d or 1m for typical monitoring') and clarifies the 'value' parameter's two acceptable forms (ticker or CIK), providing a small but meaningful edge over the raw schema.

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 this is a change feed for a company over a recent window, with concrete example queries ('What's new with X'). It names the specific data sources (SEC EDGAR, GDELT/GNews, USPTO) and explicitly distinguishes it from the sibling tool entity_profile, making its purpose unmistakable.

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?

Provides explicit usage context with query paraphrases and fallback behavior (GDELT→GNews). Directs users to entity_profile when they need a static profile, which is a clear alternative. This gives strong when-to-use vs. when-not-to-use guidance.

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