reading_open_card

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

The readOnlyHint annotation already covers the read-only nature, and the description adds useful behavioral context by stating that the tool returns an image and that the image is intended for Claude to view. It does not contradict the annotation and provides a return expectation beyond what structured metadata offers.

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, front-loaded sentence with no filler. Every part contributes meaning: the action, the target resource, and the output purpose are all covered efficiently.

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 one-parameter read-only tool, the description is largely complete: it identifies the input concept and the output form. It does not describe error cases or card availability, but those are not critical given the tool's simplicity and the presence of a readOnlyHint annotation.

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 provides no description for cardId, and the description only adds the context that the card must be one that has been collected. It does not explain where to obtain cardId or what format it should take, but the single required parameter is simple and reasonably self-explanatory. The description offers minimal additional semantic value.

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 states a specific verb ('open'), a specific resource ('one collected reading card'), and the output form ('return it as an image for Claude to view'). This clearly distinguishes it from sibling tools like reading_list_cards and reading_collect_card while making the tool's 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 wording 'collected reading card' implies this tool should be used after a card has been collected, but it does not explicitly state when to use this over alternatives or mention any exclusions. The guidance is implied rather than explicit, so it is adequate but not strong.

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