reading_save_card

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

With no meaningful annotations beyond the title, the description carries the behavioral burden and does disclose the key side effect: a local image file is written and its absolute path is returned. It also clarifies the 'collected' precondition. It could say more about overwrite behavior, file format, or write permissions, but for a simple rendering action this is solidly transparent.

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 one concise, active-voice sentence that front-loads the action and includes no filler. Every word earns its place.

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 one-parameter tool with no output schema, the description is functionally complete: it states the input condition, the operation, the artifact produced, and the returned value. Minor details like file format or error behavior are not necessary for correct invocation at this complexity level.

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 input schema provides only a bare string `cardId` with no description, so the description must compensate. It adds the meaningful constraint that the card must already be 'collected' and identifies the target entity as a reading card, but it never explicitly explains how to obtain or format `cardId`. For a single self-named parameter, this is adequate but thin.

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 names a concrete action ('Render'), a specific resource ('one collected reading card'), and a deliverable ('local image file' and 'absolute path'). This clearly differentiates it from sibling tools like reading_open_card or reading_collect_card, which do not export an image file.

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 implies the correct use case: when you need a local image export of a card that has already been collected. However, it does not explicitly state when to prefer this over alternatives such as reading_open_card or reading_collect_card, nor does it mention any exclusions.

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