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

With no annotations provided, the description must carry the behavioral burden; it does disclose ordering ('newest first'), output fields, and auth ('No key needed'). It omits pagination, result caps, and default behavior when no filters are supplied, and the sentence about get_regulation carrying last_read_at_source is ambiguous about whether it describes this tool's output or another tool's.

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 core payload is front-loaded in the first sentence and there is little waste. The trailing sentence about get_regulation and last_read_at_source feels appended and slightly muddies the paragraph rather than reinforcing the tool's purpose.

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?

There is no output schema, so the description does useful work enumerating returned fields, but it leaves open how many changes are returned by default, whether results are paginated, and how far back the history goes. For a read-only history endpoint with zero annotations, that is adequate but not complete.

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 description coverage is 100%, so both parameters and the YYYY-MM-DD format are already documented in the schema. The description only restates the filter names without adding new meaning such as default windows or how regime interacts with since, so the baseline of 3 applies.

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 names a specific verb and resource ('List the dated changes to NorthPoint's regulations library') and enumerates the returned shape (from -> to, why, source text, newest first). It also implicitly separates itself from get_regulation by framing this as change history rather than current rule text.

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?

It gives filtering guidance ('Filter by since ... and regime') and references the sibling get_regulation, implying this tool is for historical deltas. However, it never states explicitly when to prefer get_regulation or lookup_regulation over this tool, so the routing decision is left to inference.

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