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

Beyond the annotations (readOnlyHint=false, destructiveHint=false), the description discloses key behaviors: it is synchronous and slow (1-3 min, wait, don't retry), has a rate limit (20 calls/hour/website), costs 1 AI brain credit charged after work and not refunded on failure, requires subscription or trial, and preserves topic, facts, tone, language, links, and images. It also states the output format (improved markdown and score before/after). This fully informs the agent of side effects, latency, cost, and constraints.

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 description is dense but every sentence earns its place. It opens with the core action and scope, then moves to output, usage, failure behavior, latency, rate limits, cost, auth, and a parameter hint, in a logical order. There is no fluff or repetition; it is a compact, well-structured paragraph that front-loads the most critical 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?

Given the tool's complexity (8 params, output schema, multiple constraints), the description covers all necessary context: what it does, when to use it, how to handle the result, failure conditions, latency, rate limiting, cost, auth, and parameter specifics. Since an output schema exists, the description appropriately does not restate return structure but adds the score-before/after detail. Nothing an agent needs to correctly invoke this tool is missing.

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 already provides descriptions for all 8 parameters (100% coverage), so the baseline is 3. The description adds extra value by clarifying the inline nature of the content ('content you pass inline') and by giving specific guidance for website_id ('Pass website_id when the account has several websites (see get_account)'). It also explains the relationship of target_keyword to the checks. These additions lift it above the baseline, though not dramatically.

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 states a specific verb ('rewrites'), a resource ('content you pass inline'), and the precise goal ('fix failing on-page SEO checks') while enumerating the checks (keyword in intro, subheadings, density, etc.). It distinguishes itself from the sibling edit_article_with_ai by explicitly noting it works on inline content and not stored articles, so an agent can immediately tell what it does and what it does not do.

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 gives explicit when-to-use guidance: it states that content does not need to be in BlogSEO, that nothing is saved, and that for stored articles one should use edit_article_with_ai. It also warns that the tool fails before charging when all body-level checks pass, preventing wasted calls, and provides rate-limit and cost details. This is a model of usage direction.

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