Readwise MCP HTTP Server

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

With no annotations provided, the description carries full burden and does well: it discloses the mutation behavior (add/remove), the side effect of tag creation when adding, and the return value format. However, it doesn't mention error conditions (e.g., what happens if highlight_id doesn't exist), permission requirements, or rate limits, leaving some behavioral aspects uncovered.

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 perfectly front-loaded with the core purpose in the first sentence, followed by specific usage instructions and return value information. Every sentence earns its place with no wasted words, making it highly efficient and scannable.

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 a mutation tool with 3 parameters (0% schema coverage), no annotations, but with an output schema, the description is nearly complete: it covers purpose, usage, parameter semantics, and return format. The output schema likely handles return value details, so the description appropriately focuses on behavior. Minor gaps remain in error handling and permissions.

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?

With 0% schema description coverage, the description must compensate fully, which it does excellently: it explains the meaning of the 'action' parameter with enum values ('add' vs 'remove'), clarifies that 'tag' refers to a tag name (with creation behavior), and implies 'highlight_id' identifies the target highlight. This adds crucial semantic context beyond the bare 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 clearly states the specific action ('Add or remove a tag on a highlight') with the exact resource ('highlight'), distinguishing it from siblings like create_tag or delete_tag which handle tags independently. It precisely defines the tool's scope without ambiguity.

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 explicit guidance on when to use each action ('Use action='add' to tag a highlight... Use action='remove' to untag it'), including the behavioral consequence ('creates the tag if it doesn't exist'). It clearly differentiates this from sibling tools like create_tag (which creates tags independently) or update_highlight (which modifies highlight content).

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