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

Annotations already cover the safety profile (readOnlyHint=true, destructiveHint=false, openWorldHint=false), so the bar is lower. The description adds useful return-content context — that each entry carries a group and parameter ranges — which goes beyond the annotations. It stops short of covering pagination, size of the catalog, or whether results are project-scoped.

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?

One short, front-loaded sentence fragment with zero padding. Nothing is wasted, but the fragment form skips obvious cheap wins (a leading verb, a note on what to do with the results) that would cost few words.

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?

This is a simple read-only, zero-required-parameter listing tool whose annotations already declare safety, and the description states what the returned entries contain. The main remaining ambiguity — whether the catalog is global or project-scoped, and how it relates to discovery before add_effect — is modest given the tool's simplicity.

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% and the single optional projectId is fully documented in the schema ("Project to act on (default: the open one)"), so the schema carries the parameter burden. The description adds nothing about projectId and does not explain whether the catalog varies per project. Baseline 3 applies.

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 effect catalog: every effect type, its group and parameter ranges" names the resource precisely and, via the word "catalog," distinguishes this reference listing from the applied-effect siblings (add_effect, remove_effect, update_effect, clear_effects). It never uses an explicit verb, so it is slightly less crisp than a 5, but an agent can still tell it apart from siblings without opening the 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?

The description gives no when-to-use framing or exclusions. It does not say to call this before add_effect/update_effect to discover valid effect names and parameter ranges, nor does it clarify that it returns the catalog rather than effects already applied to a clip. The only signal is the implied contrast in the word "catalog."

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