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

With no annotations, the description carries the full burden. It discloses the required permission (mcp:campaigns:write) and the 'allowlisted' restriction, adding valuable context beyond the schema. However, it does not mention whether the update is partial or full, whether it returns the updated campaign, or any side effects, leaving some behavioral gaps.

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?

Two concise sentences front-load the verb and resource, list key fields, and state auth requirements. No filler or redundant phrasing. Excellent structure.

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?

The tool has moderate complexity (7 params, no output schema, no annotations). The description covers purpose, allowed fields, and permissions, but does not explain update semantics (e.g., partial vs. full update) or the response format. Given the lack of annotations and output schema, it is adequate but not fully complete.

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 the baseline is 3. The description adds the 'allowlisted' modifier and lists field names, which reinforces the schema but does not provide new syntax or format details. It adds marginal value beyond the structured parameter descriptions.

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 clearly states the action ('Update') and the resource ('allowlisted fundraiser campaign fields') and lists specific fields (title, description, x handle, images, links), which differentiates it from sibling tools like update_endpoint and update_product. It is specific and unambiguous.

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 implies usage for updating existing campaigns, and the context is clear given the sibling tool create_campaign exists. It does not explicitly name alternatives or exclusions, but the purpose is distinct enough that no exclusions are needed. It does not say when not to use it, but the update context is evident.

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