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

Annotations already declare readOnly/idempotent/non-destructive, and the description goes well beyond them by defining exactly what each suppression scope blocks (global = every API Platform send, marketing = only PROMOTIONAL Email API messages via metadata campaignType, transactional = non-promotional). It also clarifies the platform boundary, which is the main source of agent error here.

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 and platform exclusion are front-loaded in the first two sentences, and the scope explanation is dense with actionable detail. There is mild redundancy — the Marketing Platform caveat and the scope definitions are restated twice, and the PROMOTIONAL capitalization is noisy — but no full sentence is wasted.

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?

With 8 optional params and no output schema, the description supplies the critical missing piece by telling the agent that each returned entry carries its scope, plus what that scope blocks. It does not describe pagination behavior or result shape beyond that, a minor gap given the fully documented schema.

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%, so the baseline is 3, but the description adds real semantics the schema lacks: the schema only lists scope values while the description explains what each scope means operationally. The reason-filter values are merely restated, so the lift is partial rather than full.

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 ("List suppressed recipients on the API Platform suppression list") and immediately scopes it away from Marketing Platform campaigns, which no sibling covers. An agent can distinguish it from add_suppressions and reactivate_suppression without opening a 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?

Explicitly names the domain boundary ("This list does not apply to Marketing Platform campaigns") and enumerates the available filters and their values, giving clear selection context. It stops short of naming the sibling tool to use for adding or reactivating suppressions, so the alternative routing is implied rather than stated.

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