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

Annotations already declare readOnlyHint, openWorldHint, and idempotentHint, but the description adds valuable behavioral details: fans out to SEC EDGAR, GDELT→GNews fallback, USPTO patent data with a known sunset date and soft-failure mode, and returns structured changes with citation URIs. No contradictions 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 more verbose than ideal, but it is front-loaded with user intent phrases and efficiently packs source details, fallback logic, parameter formats, return shape, and an alternative tool. Every sentence contributes useful context, though the length could be trimmed slightly without losing value.

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 adequately explains the return structure: grouped changes by source, total_changes count, and citation URIs. It also covers source-specific caveats (USPTO soft-fail, GNews fallback) and the `since` parameter's formats, making the tool self-contained for agent 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 coverage is 100% and includes descriptions for all three parameters. The description reinforces the `since` parameter's accepted formats and typical monitoring values, but this largely duplicates schema content. It does not add significant new meaning beyond the schema, so baseline 3 is appropriate.

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 provides a change feed for a company over a time window, with specific verbs like 'What's new' and 'updates on'. It distinguishes itself from sibling entity_profile by explicitly noting that entity_profile should be used for static profile data instead.

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 explicit usage examples ('What's new with X', 'latest on Y') and provides a clear alternative: 'Use entity_profile instead when you want the static profile...'. It also explains the fallback behavior between GDELT and GNews, helping the agent decide when this tool is appropriate.

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