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

Annotations already mark this as a non-read-only, non-idempotent, non-destructive write operation. The description adds important behavioral facts: background scraping, auto-categorization, indexing, the monthly capture limit, and that duplicate URL saves are no-ops. These go beyond the structured 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 compact and front-loaded: it opens with the core purpose, then covers input forms, optional fields, background behavior, quota impact, and duplicate handling. Every sentence contributes meaningful information with no filler.

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 3-parameter write tool with no output schema, the description covers the inputs, optional metadata, background side effects, quota implications, and duplicate behavior. An agent has enough context to call it correctly and anticipate consequences.

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%, so the baseline is 3. The description adds value by clarifying title behavior for URLs (replaces the page title and skips the AI headline; leave empty unless the user asked) and explaining that the optional note stores the user's own context. This goes 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?

States a specific verb ('Save') with a clear resource ('link or text note to the user's MarkIt library') and enumerates the two content forms (URL vs plain text). This distinguishes it from sibling tools like fetch, search, and create_reminder without needing to compare schemas.

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 clear context for when to call this tool: to persist a URL or note, optionally with a user-provided title and context note. It does not explicitly name alternatives or exclusions, but the save-vs-lookup/reminder purpose is evident among the sibling tools.

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