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

Annotations already establish readOnlyHint=true and destructiveHint=false, so safety is covered. The description adds genuinely non-derivable context: the tool is reserved for the panel's quick-edit flow, must not be invoked by an agent, and returns a narrow two-field projection rather than the full card.

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?

Two short sentences with zero filler, and the critical do-not-call warning is front-loaded before the description of the return value. Every clause 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?

With an output schema present, the description needn't document return values, and it correctly avoids doing so. For a single-parameter, panel-internal read tool, the callability warning plus the field-projection note is sufficient for an agent to decide correctly (i.e., not to call it).

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?

Schema description coverage is 100%, and the schema's card_id description ('the card whose answer to show: the card_id of the front just asked') is richer than anything in the tool description. The description adds no syntax, format, or edge-case meaning beyond the schema, so the baseline 3 applies.

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 gives a specific verb+resource (returns the fields behind a card) and names its domain ('Flash's study panel only'), which differentiates it from general read tools. However, 'the two fields' is left undefined and the description leans on an access constraint rather than a crisp statement of what the tool produces.

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?

It states an explicit prohibition ('never call it yourself') and names the correct alternative ('use list_cards'), which is exactly the when-not/alternative guidance an agent needs. Nothing about selection is left to inference.

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