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

readOnlyHint=true already tells the agent this is a safe read, so the bar is lower; the description adds real value by naming the fields the history returns (including the saved HAR file location), which matters because there is no output schema. It does not mention pagination behavior, but the schema already covers limit/before/links.next.

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?

Two tight sentences that lead with the purpose and return content, followed by the endpoint mapping. Nothing is wasted, though the raw 'StatusCake: GET /pagespeed/{test_id}/history' is somewhat redundant with the stated 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?

For a read-only history tool with fully documented params and no output schema, the description supplies the missing return-field context and identifies the source endpoint. It stops short of noting pagination or that history may be empty, but nothing critical to calling it correctly is absent.

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 test_id, limit, after and before are all documented in the schema itself; the description adds no syntax or format detail for them. Baseline 3 is appropriate when the schema does the heavy lifting.

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 ('past runs of one pagespeed check') and enumerates the returned metrics (load time, file size, request count, throttling, HAR location). This cleanly distinguishes it from sibling statuscake_list_pagespeed_checks (lists checks) and statuscake_get_uptime_history (uptime history, not pagespeed).

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?

Implicit selection is clear from 'one pagespeed check' and the required test_id, so an agent can infer it is per-check history rather than a listing. However, there is no explicit when-to-use versus statuscake_get_uptime_history or statuscake_list_pagespeed_checks, and no stated prerequisites or exclusions.

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