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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds valuable behavioral context beyond annotations: it fans out to multiple sources in parallel, has a GDELT→GNews fallback, notes the PatentsView API sunset causing soft-fail, and describes the return shape (changes[] grouped by source, total_changes, pipeworx:// citation URIs). It doesn't detail pagination or rate limits, but the disclosed behavior is substantial.

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 well-organized: example queries first, then the core function, then source details, then parameter formats, then return shape, then the sibling distinction. Every sentence adds information, though the source-fallback details make it slightly long. The front-loading of example queries is effective for an agent scanning for intent.

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?

For a read-only, idempotent tool with 100% schema coverage and no output schema, the description covers the main things an agent needs: what it does, what inputs look like, what sources it hits, and when to use the sibling instead. It doesn't specify pagination or exact output field types, but the return shape is summarized and the annotations cover safety. A small gap is not explaining how 'changes' are structured beyond grouping by source, but this is acceptable given the tool's complexity.

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%, so the schema already documents all three parameters. The description adds meaning by explaining the `since` accepted formats (ISO date or relative shorthand) and giving typical usage ('30d' or '1m'), plus clarifying that `value` can be a ticker or zero-padded CIK. This goes beyond the schema's descriptions and helps an agent construct valid calls.

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 concrete natural-language queries ('What's new with X', 'latest on Y') and then states the exact function: a change feed for a company over a time window in one parallel call. It names the data sources (SEC EDGAR, GDELT→GNews, USPTO) and explicitly contrasts with entity_profile, so an agent can distinguish it from the closest sibling without opening schemas.

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 when-to-use guidance via example queries, specifies the `since` window formats, and states the alternative: 'Use entity_profile instead when you want the static profile... regardless of window.' It also discloses fallback behavior (GDELT preferred, GNews on rate-limit/5xx) and the USPTO soft-fail, which helps an agent decide whether this tool fits the task.

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