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

Though annotations at mark idempotentHint=true and destructiveHint=false, the description meaningfully expands on behavior by explaining side effects: future scheduled or claimed actions are canceled, no further outreach occurs, and campaign history is preserved. This goes beyond the annotations and helps an agent understand what 'soft-exclude' means in practice. It doesn't state permissions or reversibility, but the annotations already carry the safe, idempotent, mutation profile.

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 compact sentences cover a distinct verb, the core side effects, and a usage orientation preceding the alternative. Each sentence earns its place: the first states the operation, the second details behavior, and the third gives the decisive when-to-use instruction. No repetition or filler.

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 3-parameter tool with no output schema and minimal annotations, the description explains the full state-level effect: history preserved, future outreach canceled. It doesn't mention whether the exclusion is reversible through a sibling tool or what the mutation returns, but the schema and the sibling list (add_contacts_to_campaign) imply those details. This is adequate for an agent to correctly select and invoke the tool.

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%, so each of the three parameters is already documented in the schema. The description adds marginal meaning with 'saved contacts,' implying contact_ids must already exist, but does not comment on campaign_id or reason beyond what the schema states. Baseline 3 is appropriate because the schema already carries the parameter semantics.

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 description uses a specific verb and resource: 'soft-exclude saved contacts from one campaign.' It clarifies the key distinction from hard deletion by stating that campaign history is preserved, and explicitly frames the alternative as 'instead of deleting campaign history.' This distinguishes it from inverse siblings like add_contacts_to_campaign.

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 an explicit usage rule: 'Use this instead of deleting campaign history,' which tells the agent when choosing this tool over a harsher alternative. However, it does not state when not to use the tool, prerequisites (e.g., campaign must exist or contacts must be saved beyond the phrase 'saved contacts'), or how it compares to add_contacts_to_campaign. Context is clear but exclusions are not enumerated.

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