reading_open_card

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

Annotations already declare readOnlyHint=true, so the description adds value by stating the output is an image for Claude to view. However, it omits behavioral details such as whether the card is marked as viewed, if there are size limits, or if the card must already be in a 'collected' state. The added context is minimal but non-contradictory.

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 single sentence with no wasted words. It front-loads the verb and resource, and immediately states the output format. Every word is necessary and contributes to understanding.

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 simple read-only tool with one parameter and no output schema, the description covers the core behavior: opens a card and returns an image. It lacks error handling, success/failure signals, and the requirement that the card be 'collected,' but overall it is mostly complete given the low complexity.

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 fully explain the single parameter 'cardId'. It only implies it identifies the card ('Open one collected reading card') but does not specify format, source, or constraints (e.g., required length, how to obtain valid IDs from other tools). This is insufficient for an agent to correctly infer the parameter's meaning.

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 action ('open'), the resource ('collected reading card'), and the output ('return it as an image for Claude to view'). It effectively distinguishes the tool from siblings like reading_collect_card or reading_save_card by specifying that it opens an existing card for viewing.

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?

No guidance is provided on when to use this tool versus alternatives. The description does not mention prerequisites (e.g., card must be collected), exclusions, or situations where another tool would be more appropriate. Among many sibling tools, this lack of differentiation leaves the agent uncertain.

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