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

Annotations already cover read-only, idempotent, non-destructive, and non-open-world behavior, so the safety profile is known. The description adds useful behavioral context beyond annotations: the signed-in organization scope, the 'processed' batch constraint, the allowlisted metadata, and the 20-variant cap. No claims contradict the annotations.

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 sentences with no waste: the first states the core action and target, and the second gives return constraints and a key non-effect. The description avoids repeating schema properties and front-loads the most decision-relevant 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?

For a single-required-parameter tool with a full output schema and rich read-only annotations, the description is complete enough for correct invocation. It covers the selection criterion (exact id), the scope (signed-in organization), the return type, and behavioral limits. An agent does not need additional guidance to use the tool correctly.

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 already documents batchId as the exact batch id from list_batches with length constraints, so schema description coverage is 100%. The description adds only minor parameter-related context such as 'exact id' and organization scope, which is helpful but not substantial enough to exceed the baseline for fully documented parameters.

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 uses a specific verb ('Fetch'), identifies the resource ('one processed image batch'), and states the retrieval method ('by exact id') and result shape ('allowlisted metadata plus at most 20 first-party resized or reformatted variants'). It also differentiates from mutating operations by explicitly stating it does not create or transform media, making it clearly distinct from siblings like delete_batch.

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 clearly implies when to use the tool: when the agent has a specific batch id and needs the batch-detail view for the MCP App. It provides an explicit exclusion ('does not create or transform media') but does not explicitly name alternatives such as list_batches for finding ids or delete_batch for removing a batch, leaving a small inference gap.

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