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

Beyond the annotations (readOnly, openWorld, idempotent, non-destructive), the description discloses important behavioral traits: parallel fan-out to multiple sources, GDELT→GNews fallback on rate limits/5xx, and the PatentsView API sunset causing a soft-fail until reactivation. This is valuable context not captured by annotations or schema.

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 a single dense paragraph but front-loads the core purpose and then logically covers sources, parameters, return format, and alternatives. Every sentence adds operational value, though the density could be improved with bullet points for readability. It is appropriately sized for the tool's complexity.

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 no output schema, the description compensates by specifying the return shape (changes[] grouped by source, total_changes count, pipeworx:// citation URIs). It covers all parameters, data sources, failure modes, and sibling differentiation. The description is fully self-sufficient for an agent to invoke the tool correctly.

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% for all 3 parameters, but the description adds semantic depth beyond the schema: it explains the `since` parameter accepts ISO dates or relative shorthand with concrete examples ('7d', '3m'), and clarifies that `value` can be a ticker or zero-padded CIK. This goes beyond the bare schema descriptions, though some redundancy exists with schema text.

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: 'change feed for a company in the last N days/weeks/months in ONE parallel call.' It lists specific data sources (SEC EDGAR, GDELT/GNews, USPTO) and explicitly differentiates itself from entity_profile, making its purpose unambiguous and distinct from sibling tools.

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 provides explicit usage guidance: it maps natural-language queries ('what's new with X') to the tool, and gives an explicit alternative ('Use entity_profile instead when you want the static profile'). It also clarifies fallback behavior and encoding limitations, leaving no ambiguity about when to choose this tool.

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