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

Annotations already declare readOnlyHint=false, idempotentHint=true, and destructiveHint=false, so the description is not required to repeat those. It adds the scope 'typed/meta fields' but does not disclose deeper behavioral aspects such as whether unspecified fields are preserved or reset, or any constraints on customType/visibility transitions.

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?

The description is a single, tightly worded sentence that immediately communicates the action and scope. It is appropriately front-loaded with the verb and wastes no words.

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 presence of an output schema and annotations reduces the burden on the description. It correctly identifies the tool's purpose and differentiates it from siblings, but could benefit from noting batch behavior (items array) and update semantics (replace vs merge). Overall, it is minimally adequate but not comprehensive.

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%, so the description must compensate for parameter understanding. However, it only vaguely mentions 'typed/meta fields' and does not explain any of the parameters (campaignId, entryId, title, tags, customType, visibility). The schema itself only describes entryId, leaving the rest unclear.

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 specific resource ('Custom-typed mnemons'), and further narrows the scope to 'typed/meta fields', distinguishing it from sibling tools like update_mnemons_content and other type-specific update tools.

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 usage context is implied by the type-specific name and description, but no explicit guidance is given on when to choose this over alternatives or when not to use it. It lacks statements like 'use this for custom mnemons, not for other types' or references to sibling tools.

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