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

The description adds real context beyond the annotations: 'Uses one read (two to compare)' discloses a credit/consumption cost, and 'saves the result in the user's Puley history' explains why readOnlyHint is false on an otherwise read-like operation. openWorldHint and idempotentHint behavior are left unaddressed, and no fallback behavior is described if an archive has no snapshot.

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?

Front-loads the scope statement, then branches on `since` and `show`, with the user-question framing at the end. Dense but every clause carries information. Minor cost: the parenthetical and nested clauses make the second sentence a bit run-on.

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?

With no output schema, the description usefully indicates what results look like (change summary vs. historical snapshot vs. archive timeline) and notes the read cost. Remaining gaps are small: no snapshot-found behavior, no result format or size expectations. Overall adequate for a three-parameter archival lookup.

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 0%, so the description has to carry the parameters, and it does explain `since` ('2024, 2024-06-30 or 1 year ago') and the `show=page` mode usefully. However the `show` parameter's default and other values are only implied, and `link` is never characterized (URL form, required). It partially but not fully compensates for the coverage gap.

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?

States a specific verb and resource: retrieving a page's past from web archives (Wayback Machine, then Common Crawl), plus diffing between then and now. That is far more specific than a name restatement. It does not explicitly name a sibling such as whats_changed or see_page to draw the boundary, so it stops short of a 5.

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?

Gives concrete when-to-use branches: with `since` it answers 'did they change their prices or terms?', with `since` + `show=page` it shows the page as it was, and without `since` it lists archive dates. It also frames the user questions it answers. It never states when to prefer a different tool instead.

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