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

Goes beyond annotations with genuinely decision-relevant behavior: 'No media generation, credit charge or library change', plus 'Returns a new brief and quote'. That tells the agent this is a free, planning-only mutation, which annotations (readOnlyHint=false, destructiveHint=false, idempotentHint=false) alone don't convey. It stops short of describing concurrency failure behavior for a stale expected_brief_revision.

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?

Front-loaded with the action, then constraints, then return behavior, then the workflow tip — a sensible ordering with no filler. The telegraphic 'Revises the selected looks using the named brief flow (default: all its looks)' is slightly compressed and ambiguous about which entity 'its' refers to.

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 9-parameter planning mutation with no output schema, it covers the essentials: what is created, what is returned, that no credits or library state change, and the recipe_key handoff. Missing pieces are minor — no sibling routing and no error/stale-revision behavior — but an agent can call it correctly from this.

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?

At 67% schema coverage the schema already documents board_id, look_keys, recipe_key, resolution, shot_index and aspect_ratio; the description mostly restates the 'shared across the shoot' framing already in those fields. Its real added value is flagging that the current brief revision is required (expected_brief_revision, which has no schema description), but camera, brief_id and the revision semantics stay unexplained.

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 and resource: 'Add a base image shot or revise its camera', and clarifies it revises looks using a named brief flow. The two-mode framing (append vs. revise) is clear, but the description never names the nearby siblings (plan_shoot_camera_change, plan_shoot_edit, plan_shoot_upscale) that an agent would otherwise confuse it with.

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?

'Requires the current brief revision' and 'Read the returned recipe_key before the next edit' give sequencing and preconditions, which is useful. However, there is no explicit statement of when to choose this over plan_shoot_camera_change or plan_shoot_edit, so selection between planning siblings remains inferred.

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