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

Goes well beyond the annotations by disclosing billing semantics: the revoking key pays for new recipients from resume onward, ownership attribution stays with the original key, and the call is free. That is exactly the kind of cost/consequence context annotations cannot convey. It does not describe what happens to messages queued at pause time, which keeps it off a 5.

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 short sentences, action and precondition front-loaded, billing caveat last. Dense rather than padded. Slightly cryptic phrasing ('the key that paid for it') costs a point on immediate legibility.

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 single-parameter state-transition tool with no output schema, it covers the essential context: precondition, cost, and key attribution. Missing only post-call behavior (what the campaign state or return looks like), which keeps it at 4.

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?

Only one parameter and schema coverage is 100%, with the schema already tying campaign_id to outreach_save_campaign's answer. The description implies the campaign must be paused but adds no format or retrieval detail beyond the schema, so 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?

States a specific verb and resource ('Send again from a paused campaign'), which unambiguously separates it from siblings like outreach_start, outreach_pause and outreach_stop without needing their schemas.

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 a clear precondition for use (the pause cause must be fixed, with paused_reason as the pointer) — that is real when-to-use guidance. It stops short of naming the alternatives explicitly (e.g. 'use outreach_start for a campaign that never ran'), so a 4 rather than a 5.

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