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

Beyond the readOnly/idempotent/non-destructive annotations, the description discloses substantial behavior: auto-tiering with stealth profiles, the full outcome taxonomy (success | teaser | thin_content | paywall | …), inline truncation at 80k chars with a download_full_url that expires, and cost=0 for unsupported targets. None of this contradicts the annotations.

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 and front-loaded with the core fetch-and-extract purpose before the behavioral mechanics. The outcome list and unsupported-target enumeration are long but information-bearing, and each sentence earns its place; the only structural nit is that it is one large paragraph that could benefit from light grouping.

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 carries the burden of explaining return behavior—it covers the YAML frontmatter fields (url, outcome, total_chars), large-page truncation via truncated_chars + download_full_url, and outcome meaning. Minor gaps remain (what total_chars counts, shape of html/json outputs), but an agent can invoke the tool correctly with what is provided.

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%: url, format (with enum and per-format meaning), and selector (with the anchor-id expansion rule) are already documented in the input schema. The description reinforces that markdown is the default output but adds no new parameter-level meaning, so the 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?

The description opens with a specific verb and resource: 'Fetch a single web page and extract clean content.' This distinguishes it cleanly from siblings like glim_web_search and the platform-specific get tools, and it further sharpens the boundary by stating which platform-specific pages are covered ('Threads and Instagram profile pages ARE supported') and which are not.

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 exclusions: it enumerates permanently unsupported targets ('Bluesky search, Instagram post/reel and tag/explore pages… Pinterest search, g2.com, Truth Social, Xiaohongshu') and instructs the agent to 'Read outcome to classify the result.' It does not, however, name sibling tools as alternatives for those excluded cases, so the redirect-to-alternative guidance is only implied.

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