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

Annotations already declare readOnlyHint=true, idempotentHint=true. The description adds critical behavioral details: auto-tier SSR handling, paywall detection, stealth profiles, outcome codes, truncation with download URL, and permanently unsupported targets. No contradictions with 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 long but well-structured, front-loading the main action and outcome classification. Every sentence adds value, though some technical details (e.g., list of unsupported targets) could be condensed without losing clarity.

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?

Despite no output schema, the description fully documents return format (markdown with YAML frontmatter), outcome codes, truncation behavior, and unsupported targets. It covers edge cases and context needed for correct invocation, making it highly complete for a complex tool.

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?

Input schema has 100% parameter coverage, but the description adds meaningful context: it clarifies that `json` format returns a structured SSR blob for specific sites, and `selector` scopes extraction. This goes beyond the schema's brief descriptions, earning a 4.

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 clearly states it fetches a single web page and extracts clean content, with a specific verb ('Fetch') and resource ('web page'). It distinguishes from sibling tools (e.g., glim_reddit_get, glim_youtube_get) by focusing on arbitrary URLs rather than platform-specific endpoints.

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 provides extensive usage guidance: it lists supported and unsupported sites, outcome classification, truncation behavior, and when to use different formats. It implicitly distinguishes from siblings by covering general web fetching vs. platform-specific tools.

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