set_post

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

No annotations exist, so the description carries the full behavioral burden and does so well: it builds a compositor tree, refuses to replace a tree it did not create, applies partial updates, and returns the active settings. Mutation, idempotence-adjacent semantics and a failure/refusal condition are all disclosed.

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?

Purpose is front-loaded, followed by per-effect parameter blocks that are dense but each carry needed detail; no filler sentences. It is long and backtick-heavy, but for a 6-parameter tool with zero schema documentation the length is largely earned.

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?

No output schema exists, and the description closes that gap by stating it returns the active settings. Combined with engine compatibility, viewport invisibility and the tree-ownership refusal, an agent has everything needed to call it 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?

With 0% schema coverage this description does the heavy lifting: ranges, defaults and meanings for vignette.strength/softness, glare.type enum values, threshold, size, saturation, gamma, exposure in stops, and contrast bounds. Minor mismatch: it says vignette=false disables an effect, but the schema types those params as object|null only, leaving a small ambiguity about how 'off' is expressed.

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 ('Set post-processing for render_final') and enumerates exactly which effects it controls (vignette, glare, colour, exposure, contrast). An agent can distinguish it from render_final and the many mesh/material siblings without opening any schema.

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 strong operating context: it works with every engine, is not shown in the viewport, partial calls change only what you pass, false disables a single effect, and reset=true wipes everything the tool set. It does not explicitly state when to use it relative to render_final or alternatives, so it stops short of a 5.

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