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

Annotations already carry readOnlyHint/idempotentHint/destructiveHint=false, so the bar is lower, and the description still adds real behavior: the implicit default filter (only campaigns accepting offers) and the fields returned (dates, type, participation rules). It also notes the environment constraint ('Demo shop / sample data'), which annotations do not cover.

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, each carrying information: purpose, default-filter behavior, and cross-tool linkage. The environment tagline is mildly extraneous but short and useful; nothing is padded.

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 an output schema present, return values need not be described, and annotations cover the safety profile. The description supplies purpose, default scope, and the follow-on tool, leaving only the distinction from campaigns_check uncovered.

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 67%, with name and account documented in-schema. The description adds meaning to the status parameter by explaining that omitting it restricts results to campaigns still taking offers, which the enum alone does not convey.

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+resource ('campaigns the seller can join') and enriches it with content ('dates, type and participation rules'), which is more than a restatement of the name. It partly differentiates from siblings by pointing to campaigns_propose, but never contrasts itself with campaigns_check, leaving one sibling boundary implicit.

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?

'Without a status only campaigns that still take offers are listed' tells the agent what the default scope is, and 'Use the id with campaigns_propose' establishes the downstream flow. It gives clear context but no explicit when-not-to-use or comparison against campaigns_check.

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