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

Annotations already cover the safety profile (readOnlyHint, destructiveHint=false), and the description adds real context beyond them: the audit targets the LIVE version rather than the workspace, findings are ordered worst-first, and each comes with a one-line fix. It doesn't cover limits (e.g., container size, rate/timeouts), so not a 5.

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: the check list is front-loaded as the core purpose, and the follow-up pairing advice is the only secondary content. Dense but every phrase carries information.

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?

There's no output schema, and the description compensates by describing the shape of results (prioritized findings each with a one-line fix). The optional-parameter behavior is handled by the schema. Minor gap: nothing about what happens if no container is resolvable or how large/multi-container accounts behave.

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?

With one parameter at 100% schema coverage, the schema already documents the 'GTM-ABC123' format and the 'only needed when there's more than one' rule. The description adds nothing about the container argument, so baseline 3 applies.

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 ('Check') and resource ('the LIVE version of a GTM container') and enumerates the concrete problems it detects, which clearly separates it from gtm_container_overview, gtm_list_tags, and gtm_list_triggers_and_variables (those list; this diagnoses). An agent can pick it without opening any 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?

Gives clear operating context: it audits the LIVE (published) version, and recommends pairing with run_report by eventName or Google Ads conversions to confirm impact. It does not explicitly exclude the sibling tools (e.g., say to use gtm_container_overview first for inventory), so it falls just short of a full when/when-not statement.

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