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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false. The description adds substantial behavioral context: fans out to multiple sources in parallel, GDELT→GNews fallback mechanism, USPTO soft-fail, return structure (changes[] grouped by source, total_changes count, pipeworx:// URIs). This goes well beyond what annotations provide.

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 but packs in all essential information without redundancy. It is front-loaded with example query patterns, which is helpful. Slightly long but every sentence earns its place; a minor structure improvement could break into sections, but current form is still effective.

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?

Given the tool's complexity (multiple sources, fallback behavior, two input formats for 'since'), the description covers all needed context: what sources are queried, how fallbacks work, return structure, and explicit cross-reference to sibling tool. No output schema exists, but the description explains the return format adequately.

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 baseline is 3. The description adds value by explaining 'since' accepts ISO dates or relative shorthand with examples ('7d', '30d', '3m', '1y') and explicitly recommends '30d' or '1m' for typical monitoring. Also clarifies 'value' can be ticker or CIK. This extra semantic context justifies a 4.

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 in the last N days/weeks/months in ONE parallel call', with example queries like 'What's new with X'. It specifies multiple data sources (SEC EDGAR, GDELT/GNews, USPTO) and distinguishes itself from the sibling tool 'entity_profile' by noting entity_profile is for static profiles.

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 tool explicitly tells when to use it (for 'What's new' type questions) and when to use the alternative ('Use entity_profile instead when you want the static profile'). This clear guidance on tool selection is excellent.

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