Readwise MCP HTTP Server

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

With no annotations provided, the description carries the full burden. It discloses that the service 'fetches and parses the article automatically,' which is useful behavioral context. However, it lacks details on permissions, rate limits, error handling, or what the output contains (though an output schema exists). The description doesn't contradict any 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 front-loaded with the core purpose, followed by key constraints and parameter details. Every sentence adds value: the first states the action, the second explains automation and URL constraints, and the third clarifies the location parameter. No wasted words or redundancy.

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 moderate complexity (5 parameters, 1 required) and the presence of an output schema (which handles return values), the description is largely complete. It covers the primary function, key constraints, and the most critical parameter. However, it lacks details on optional parameters (title, tags, notes) and behavioral aspects like error cases.

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 0%, so the description must compensate. It explains the 'location' parameter's purpose, enum values, and default, adding meaningful semantics beyond the schema. However, it does not cover the other four parameters (url, title, tags, notes), leaving gaps in understanding their roles and formats.

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 the specific action ('Save a URL') and target resource ('to Readwise Reader'), distinguishing it from sibling tools that handle highlights, tags, books, and documents. It explicitly positions this as 'the primary way to add content to Reader,' making its purpose unambiguous.

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 clear context for when to use this tool ('the primary way to add content to Reader') and mentions constraints ('Only http:// and https:// URLs are accepted'). However, it does not explicitly state when not to use it or name alternatives among the sibling tools (e.g., for non-URL content).

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