show_reader_prefab_card

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

No annotations are present, so the description carries the full burden. It does disclose the return shape ('ToolResult with PrefabApp structured content plus plain-text fallback'), which is genuinely useful behavioral context, but it says nothing about whether rendering has side effects, permissions required, or whether the output is static vs. live data.

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 short and uses clear section headers for Return Format and Examples. It wastes a line restating the tool name verbatim ('show_reader_prefab_card - ...'), but otherwise every sentence carries information.

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?

With no output schema, the description's Return Format section compensates adequately by naming ToolResult and the PrefabApp structured content. However, for a tool with no parameters and no annotations, the description never explains the card's purpose beyond 'stats', leaving the agent without a clear mental model of the rendered content.

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 tool takes zero parameters and the schema confirms this with additionalProperties: false, so there is nothing for the description to document. Baseline 4 applies for a parameterless tool.

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 the resource ('reader prefab card') and frames it as a stats card for 'list/status/stats coverage', which hints at its role as a renderable summary view. However, 'Prefab stats card' is jargon and the verb 'show' conveys little about what the card actually contains or when it appears, and it does nothing to distinguish itself from sibling tools like reader_ops.

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?

There is no guidance on when to invoke this tool versus reader_ops or the other reader-related siblings. The single empty-object example ('{} -> renders reader stats card') implies it takes no input but gives no conditions under which an agent should prefer it over alternatives.

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