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

The readOnlyHint annotation already establishes this is a safe read operation, so the description carries a lower burden. It does add the meaningful distinction between public/system prompts and workspace prompts and the is_custom gate, but says nothing about ordering, pagination, or what happens if prompt_id is invalid or belongs to another workspace.

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-loaded summary followed by a two-item numbered breakdown keyed to the request enum. Efficient and scannable, with no filler sentences; the only slack is that mode 2's optional parameters are packed into one clause.

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?

An output schema exists, so return values need not be described. Still, for a 5-parameter mode-switching tool with zero schema description coverage, the description omits the valid prompt_type values and the precondition for the details path, leaving real gaps an agent would have to guess at.

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 0%, so the description must carry parameter meaning, and it does map every parameter to a mode (workspace_id + prompt_type for menu; prompt_id + is_custom + workspace_id for prompt_details). However, it gives no value domain for prompt_type, no type/format hints, and no note that is_custom is only meaningful on the details path.

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 opening sentence states a specific verb and resource: 'Browse the PageSpeed Insights prompt catalog.' The numbered modes then make the two capabilities concrete. It does not differentiate against siblings (execute_action, query_contexts, query_data), but those are dissimilar enough that confusion is unlikely.

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 two request values are explained, which implies the usage split, but there is no explicit when-to-use-this-vs-alternatives guidance and no prerequisites (e.g., whether a workspace_id must be known ahead of time or can be discovered from the menu call). Guidance is implied rather than stated.

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