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

Annotations already declare readOnlyHint=true, so the agent knows this is a safe read operation. The description adds useful context about what the returned data contains (asset ids, saved guidance in metadata.continuityGuidance). However, it doesn't describe the return format or whether the list is ordered, which would be useful but not critical for a read-only list tool.

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?

Three sentences, each earning its place: the core action, the sibling distinction, and the metadata location. The most important information is front-loaded, and there is zero waste.

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 read-only list tool with one fully-documented parameter and readOnlyHint annotation, the description is nearly complete. It explains the relationship to get_scene_assets and points to where guidance data lives. The only minor gap is the lack of detail about the response shape, but no output schema exists and the description gives enough for an agent 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?

Schema coverage is 100% — the single parameter shot_id is fully described in the schema as 'Shot id (episode_shots row)'. The description doesn't add parameter-level detail beyond that, but with full schema coverage, the baseline of 3 is appropriate.

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 a specific verb ('List'), resource ('continuity reference images'), and scope ('attached to one shot'). It also distinguishes itself from get_scene_assets, which returns the same data but for a whole scene. An agent can tell exactly what this tool does and how it differs from its closest sibling.

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?

Explicitly names the alternative (get_scene_assets), explains the difference (whole scene vs one shot), and gives a concrete when-to-use condition ('when you need the asset ids, for example to remove one or update its guidance'). This is clear routing guidance with no ambiguity.

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