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

Annotations already declare readOnlyHint=false, destructiveHint=false, openWorldHint=false, so safety is covered structurally. The description adds nothing behavioral beyond that – it doesn't say whether the previous keyword is discarded, whether adjacent brief fields (title, instructions) are unaffected, or whether the change requires brief approval state.

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 or redundancy. It is efficient, though it is arguably too terse for a five-parameter mutation tool rather than deliberately concise.

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 five required parameters, no output schema, and only a minimal description, an agent lacks what it needs to build a correct call – particularly the project/site/plan/brief ID hierarchy and the effect of the change. The description is underspecified for the tool's complexity.

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 0% across 5 required parameters, so the description carries the full burden and mostly fails. Only the mapping of 'target keyword' to the `phrase` parameter is implied; the roles and required nesting of projectId, siteId, planId, and briefId are never explained, nor is the 2-120 character constraint.

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 ('change') and resource ('target keyword of one article brief'), which clearly separates it from update_content_brief_instructions. It does not explicitly name the sibling it might be confused with, so it lands just below full marks.

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?

There is no when-to-use guidance, no prerequisites, and no mention of alternatives such as update_content_brief_instructions or reschedule_content_brief. The agent must infer applicability entirely from the name.

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