Compare Strategies

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

With no annotations, the description carries the full burden, and it does disclose what the response contains (score deltas across all categories plus key metric comparisons). However, it omits operationally important traits such as the fact that it effectively runs two PSI analyses (latency/cost), any API key or quota requirements, and whether results are cached.

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 sentences, zero filler, with the core comparison scope front-loaded in the first sentence and the outcome in the second. Nothing is repeated from the name or title.

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 adequately summarizes the return surface (score differences and metric comparisons). It is close to complete for a simple two-parameter read tool, losing a point only for the missing usage routing and cost/quota context.

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 url and categories are already documented in the schema; that sets the baseline at 3. The description adds nothing about parameter behavior beyond the phrase 'across all categories', which only loosely gestures at the categories default.

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 (compare) and a precisely scoped resource (mobile vs desktop PageSpeed Insights results side-by-side for a URL). No sibling tool does a cross-strategy comparison, so an agent can distinguish it from analyze_url and the other single-dimension getters without opening a schema.

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 description gives a rationale ('to identify strategy-specific issues') that hints at when the tool is appropriate, but it never states when to prefer this over analyze_url or any sibling, nor any prerequisites or exclusions.

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