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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is fully covered by structured data. The description adds only the substantive behavior that the same tool serves two modes, listing and comparing, which is genuinely useful context. It does not disclose pagination behavior, what an entry or diff looks like, or what happens when only one of the compare parameters is supplied.

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?

A single sentence with no filler, and the primary purpose (see history) is front-loaded before the secondary capability (compare). It is efficient, though for a tool with two distinct modes a slightly more explicit two-clause structure would have been clearer without adding length.

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?

This is a low-complexity, all-optional-parameter read tool with rich annotations and full schema coverage, so the description does not need to carry much. However, there is no output schema, and the description never indicates what a history listing or a comparison yields, nor how the two modes interact with the compare_* and starting_before parameters, leaving an agent to infer the return shape entirely.

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 all four parameters are already documented in the schema, including the compare_from/compare_to pairing and the starting_before pagination marker. The description's phrase 'two points in it' adds only a loose conceptual frame over the schema's explicit 'version number' language. With the schema doing the heavy lifting, 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 resource and a specific verb: see the history of a site and compare two points in it. That is materially clearer than the bare name 'history' or the vaguer title 'See what changed', and it covers both the list mode and the diff mode. It stops short of naming a sibling (e.g. read_page or rollback) to contrast with, so it is clear but not sibling-differentiated.

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?

Usage is only implied: the phrase 'compare any two points' hints that supplying two version numbers switches the tool into diff mode, but there is no explicit statement of when to choose this over read_page, list_pages, or rollback. No exclusions or prerequisites are given, and it never says whether site can be omitted in multi-site connections (that lives only in the schema).

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