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

Annotations already declare destructiveHint=true and readOnlyHint=false, so the safety bar is lower; the description still adds real value by stating that deletes require confirmation, which annotations do not cover. However, for a mutation tool with nested objects it says nothing about whether updates replace or merge existing rules/application config, what side effects activation has, or how idempotency_key affects retries.

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?

A single front-loaded sentence with no filler; the operation scope comes first and the confirmation caveat follows. Its only issue is being under-specified rather than bloated, which is penalized elsewhere.

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?

Given 11 parameters, nested campaign/application/rules objects, a 7-value action enum, zero schema descriptions and no output schema, a one-sentence description leaves the agent guessing on most invocation decisions. The action-conditional requirements (which fields apply to which action) are exactly what this tool needed and does not provide.

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 0% across 11 parameters including two nested objects (campaign, application) and a rules array. The description compensates only obliquely, hinting at the code and campaign parameters through the phrase 'discount codes and campaigns'; action values, idempotency_key semantics, rules/application structure and the automatic flag are entirely undocumented.

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 names concrete verbs and the resource (discount codes and campaigns), and its 'create/edit/activate/deactivate' framing matches the action enum rather than contradicting the tool's 'update' name. It doesn't call out all seven action values (update_campaign, delete_campaign are absent) or distinguish itself from any sibling, but no sibling plausibly overlaps, so an agent can still place it.

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 note that 'deletes need MCP confirmation' is a genuine workflow precondition an agent would otherwise get wrong. Beyond that there is no when-to-use/when-not guidance, no direction on choosing among the seven action values, and no stated prerequisites such as workspace scoping.

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