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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, providing a safety profile. The description adds significant behavioral context: fan-out to multiple sources, fallback logic (GDELT→GNews on rate limit/5xx), soft-failure for USPTO, and return structure (changes[] grouped by source, total_changes, citation URIs). No contradiction with 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 a single paragraph that front-loads the primary purpose and lists sources. Each sentence serves a purpose, from parameter guidance to sibling differentiation. It is concise but somewhat dense; slightly restructuring could improve readability, but overall it is efficient and informative.

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?

With no output schema, the description explains the return structure (grouped changes, total_changes, citation URIs). It covers all parameters, sources, and fallback behavior. However, it omits edge cases (e.g., no results, invalid date) and does not elaborate on rate limits. Despite these minor gaps, it is largely complete for an agent to use the tool effectively.

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%, with each parameter having a description. The tool description adds value by providing concrete examples for `since` (ISO date '2026-04-01' and relative '7d', '30d', etc.), recommending typical usage, and clarifying that `value` accepts both ticker and CIK. This goes beyond the schema's basic descriptions.

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 explicitly defines the tool as a 'change feed for a company in the last N days/weeks/months in ONE parallel call', listing specific data sources (SEC EDGAR, GDELT→GNews, USPTO) and distinguishing it from the sibling tool entity_profile. This provides a specific verb+resource and clear differentiation.

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 gives clear context on when to use this tool (for recent changes over a time window) and explicitly contrasts with entity_profile for static profiles. It also recommends typical parameter values ('Use "30d" or "1m" for typical monitoring'). However, it does not explicitly state when not to use it beyond the sibling comparison.

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