what_changed

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

With no annotations provided, the description carries the behavioral transparency burden. It does well by disclosing that output includes amendment dates, corrections, cross-links to Federal Register rules, and URLs explaining the 'why.' It stops short of describing edge cases such as how 'since' changes results or what happens when no amendments exist.

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?

Three sentences with no wasted words. The main function is front-loaded, the cross-link context is useful, and the compare_versions follow-up is a helpful closing action. Every sentence earns its place.

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 description gives solid context about output and workflow, and the presence of an output schema reduces the need to explain return structure. However, the tool is not fully self-sufficient because the optional 'since' parameter's semantics are left unclear and 'citation' input format is not addressed.

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 only 50%: 'citation' has no schema description and 'since' only has 'YYYY-MM-DD' without explaining what it filters. The tool description does not compensate; it only uses the word 'citation' generically and never explains the optional 'since' parameter, leaving an agent to guess its intended effect.

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 'List amendment dates for a citation, plus any published corrections,' giving a specific verb, resource, and scope. It also distinguishes itself from compare_versions by explicitly positioning that sibling as the follow-up for seeing text changes.

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 clearly tells the agent to use compare_versions next to see actual text changes, which defines a workflow and differentiates this tool from a key sibling. It does not, however, describe when to choose lookup_citation or search_regulations instead, so guidance is good but not exhaustive.

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