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 of behavioral disclosure. It usefully states that 'Only the provided fields are updated' (partial update behavior) and 'Returns the full updated highlight' (output behavior), which are valuable beyond basic mutation. However, it doesn't cover important aspects like authentication needs, error conditions, rate limits, or whether the operation is idempotent/reversible.

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 concise with two sentences that each earn their place. The first sentence states the core purpose, and the second adds important behavioral details about partial updates and return values. There's zero wasted language, and information is front-loaded appropriately.

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 this is a mutation tool with no annotations, 3 parameters, 0% schema coverage, but with an output schema, the description does reasonably well. It covers the partial update behavior and return value, and the output schema will handle return format details. However, for a mutation tool, it should ideally mention permission requirements or side effects that aren't covered by the structured data.

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?

The schema description coverage is 0%, so the description must compensate. It meaningfully explains that parameters 'text' and 'note' correspond to updatable fields of a highlight, and that 'highlight_id' identifies which highlight to update. This adds crucial semantic context beyond the bare schema types. However, it doesn't clarify the meaning of null values for text/note (whether they clear the field or leave unchanged).

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 verb ('Update') and resource ('an existing highlight's text or note'), making the purpose immediately understandable. It distinguishes this from sibling tools like 'create_highlight' or 'delete_highlight' by specifying it's for modifying existing highlights rather than creating or deleting them. However, it doesn't explicitly differentiate from 'update_progress' which might be a related but different operation.

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 no guidance on when to use this tool versus alternatives. It doesn't mention prerequisites (e.g., needing an existing highlight ID), when not to use it (e.g., for creating new highlights), or direct alternatives among the sibling tools. The agent must infer usage from the tool name and description alone without explicit context.

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