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

Annotations declare readOnly/openWorld/idempotent/non-destructive. The description adds substantial behavioral context: source fan-out to SEC EDGAR, GDELT→GNews fallback with rate-limit/5xx conditions, USPTO soft-failure due to PatentsView API sunset, and 'since' format flexibility. It also documents the return payload. This goes well beyond 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 dense but every sentence carries information: query examples, source fan-out, fallback logic, param format, return payload, and an alternative attribution. It's front-loaded with usage patterns and no filler.

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?

The tool has no output schema, so the description compensates by summarizing the return structure ('structured changes[] grouped by source + total_changes count + pipeworx:// citation URIs') and all major behaviors. It could specify per-change fields, but overall it provides a complete picture for invocation.

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 100% of parameters with descriptions (type enum, since formats, value formats). The description adds little new parameter meaning beyond reminding that 'since' is the window start, which is already in schema. Baseline 3 is appropriate due to full schema coverage.

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 opens with natural-language examples ('What's new with X') then defines the tool as a 'change feed for a company in the last N days/weeks/months in ONE parallel call.' It names three concrete sources and explicitly differentiates from sibling entity_profile ('Use entity_profile instead when you want the static profile...'). This is a specific verb+resource with strong 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 explicitly tells the agent when to use entity_profile instead ('Use entity_profile instead when you want the static profile...'), and implies when to use this tool (for change tracking over a window). It also notes the single parallel call efficiency, but doesn't exhaustively list all exclusions. Still, the explicit alternative is strong.

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