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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false. The description adds substantial behavioral context beyond these: multi-source fan-out to SEC, GDELT/GNews, USPTO; rate-limit handling; PatentsView API sunset causing soft-fail; and the ability to accept ISO dates or relative shorthand. This is rich supplementary disclosure.

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 densely packed with no wasted sentences. It opens with conversational examples to illustrate intended queries, then quickly moves into mechanism and return format. Every clause adds functional information, balancing length with comprehensiveness.

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 compensates by stating the return structure: 'returns structured changes[] grouped by source + total_changes count + pipeworx:// citation URIs.' It also explains source composition, fallback logic, and the meaning of the `since` parameter. For a tool with 3 parameters, this gives a complete operational picture.

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 covers all 3 parameters with useful descriptions (100% coverage), so baseline is 3. The description adds extra value by giving explicit examples for `since` ('7d', '30d', '3m', '1y'), recommending '30d' or '1m' for typical monitoring, and reinforcing that `value` can be a ticker or zero-padded CIK. This goes beyond the schema's 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 uses multiple specific verbs and phrases ('What's new with X', 'change feed', 'Fans out to SEC EDGAR, GDELT→GNews, USPTO') that clearly define the tool's function. It explicitly contrasts with sibling tool entity_profile ('Use entity_profile instead when you want the static profile'), distinguishing this tool as the windowed-change feed.

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 an explicit alternative: 'Use entity_profile instead when you want the static profile (filings + fundamentals + LEI + patents) regardless of window.' It also explains fallback behavior for data sources (GDELT preferred, GNews when rate-limited), which guides agents on expected tool behavior.

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