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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so the safety profile is fully covered structurally. The description adds one genuine behavioral fact beyond that: the tool returns nothing useful for video Jams. It says nothing about what the images look like on return (URLs, attachments, or binary) or what happens on an invalid jamId.

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, zero filler, with the content description front-loaded and the routing/exclusion rule second. Nothing could be removed without losing 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 simple three-parameter read tool with complete schema documentation and full annotations, the description covers what an agent needs to pick the right tool. The only residual gap is the return shape, which matters somewhat for an image-returning tool but is not required for correct invocation.

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%, including the useful note that jamId accepts either a UUID or a jam.dev URL, so the baseline is 3. The description adds no parameter-level meaning beyond the schema and does not explain the intent/llm_model telemetry 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?

States the resource precisely ("the images of a screenshot Jam") and explicitly separates it from the sibling that handles the other Jam type (getFrames for video). It's a noun phrase rather than a verb+resource formulation, so the agent must infer a fetch action, but the scope and content are 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?

Gives an explicit applicability rule ("Screenshot Jams only") plus the correct alternative for the excluded case (video Jam -> getFrames). It does not address overlap with other read tools like getDetails, getFrames-adjacent, or getMetadata, so routing among the broader read family 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.