Check GTM Snippet

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

The readOnlyHint annotation already marks this as safe, and the description adds meaningful behavioral detail beyond that: what exactly is detected (IDs), what is verified (placement, noscript, duplicates). This gives the agent a good sense of the tool's results and limitations without overstating scope.

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 with no filler. The first sentence states the core action, and the second lists the concrete verifications. Every word earns its place, and the information is front-loaded.

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 single-parameter, read-only tool, the description is quite complete: it outlines the specific checks performed. It doesn't describe the output format, but with no output schema and a straightforward detection tool, the absence is acceptable. Minor gaps like whether the page is rendered or whether snippets in subframes are checked don't undermine overall callability.

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?

The schema fully describes the single 'url' parameter with 100% coverage, so the description does not need to elaborate much. It adds minimal extra meaning beyond confirming that the page is checked; the description aligns with the parameter's purpose but doesn't provide additional format or usage details.

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 uses a specific verb ('Check') and resource ('a page for Google Tag Manager (GTM) and gtag.js snippets'), and then enumerates distinct detection capabilities: container IDs, GA4 measurement IDs, snippet placement, noscript fallback, and duplicate IDs. This clearly differentiates it from sibling tools like check_datalayer or audit_tracking, which focus on other aspects of tracking.

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 description conveys a clear use case: verifying the presence and correctness of GTM/gtag snippets on a page. It does not explicitly name alternatives or state when not to use the tool, but the focused scope makes the intended usage evident given the sibling list.

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