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

Annotations already declare the safe read-only/idempotent profile, but the description adds real behavioral context beyond them: 11 items, ~12 seconds runtime, the pass/partial/fail/could_not_check status model, and the score covering only checkable items. It also discloses a non-obvious edge case - GTM container tags that can't be read are reported as could_not_check, never as missing.

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?

The opening sentence front-loads the purpose and scope before any detail, and the operational facts (11 items, ~12 seconds, status vocabulary) are grouped logically. The dense tag enumeration is slightly list-heavy but each element is load-bearing for matching, so little is wasted.

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?

No output schema exists, so the description must explain the return shape - and it does, describing per-item status, evidence, plain-English fix, and the aggregate 0-100 score with its caveat about unchecked items. Combined with the scoping and fallback disclosure, an agent has everything needed to call it and interpret results.

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 coverage is 0% and the single parameter is undocumented in the schema, so the description carries the burden; it supplies the meaning ('the website to check') and a concrete format example ('https://example.com'). Useful but minimal - it doesn't say whether a bare domain is accepted or whether non-homepage paths are honored.

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 ('quick ad tracking check of any website's homepage') and enumerates exactly what is inspected (GA4, GTM, Google Ads, Meta Pixel, Microsoft/LinkedIn tags, call tracking, consent, phone link, CTA, speed). This cleanly distinguishes it from siblings like assess_seo, assess_website and assess_ai_readiness without the agent 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 explicit scope boundaries ('Automated, homepage only, not a full ad account audit') and routes to named alternatives with the condition for each: get_advertising_offer for the service itself, request_strategy_session to talk it through. Both when-to-use and when-not-to-use are covered.

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