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

Annotations only indicate readOnly=false, openWorldHint=true, idempotentHint=false, and destructiveHint=false. The description adds meaningful behavior: background scraping, auto-categorization, indexing, quota consumption per save, and idempotent no-op behavior for duplicate URLs. It also clarifies that URL titles come from the page rather than the title parameter. This far exceeds the structured annotation coverage.

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 a compact, front-loaded paragraph. The first sentence states the core action, subsequent sentences add input modes, optional fields, background behavior, and caveats. Every sentence earns its place, and there is no redundant repetition of schema details.

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?

For a tool with no output schema and modest parameter count, the description covers all needed aspects: what counts as an item, how to choose between URL and note, optional metadata, background processing, quota impact, and duplicate behavior. An agent has enough context to invoke the tool correctly and set expectations about side effects.

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 already describes all three parameters with descriptions and constraints, so the baseline is 3. The description goes further by explaining that content can be a URL or text, that title applies only to text notes, and that note stores user context. This adds useful semantic nuance beyond the raw schema.

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 'Save a link or a text note to the user's MarkIt library', a specific verb plus resource that immediately establishes what the tool does. It also differentiates between two content modes (URL and text note), which clearly separates it from sibling tools like fetch or search.

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 explains when to use each input form: pass a URL to scrape a page, or plain text to save a note, and clarifies the optional role of note and title. It also gives practical context such as the monthly capture limit and duplicate-URL no-op. It does not explicitly name alternatives, but sibling tools are not direct substitutes for saving to the library.

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