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

Annotations declare readOnlyHint=false, idempotentHint=true and destructiveHint=false; the description adds real value beyond that by disclosing partial-update semantics ('Only the supplied fields are changed'), the authorization requirement, and that platform is immutable here. It is consistent with the idempotent annotation but does not mention failure behavior or return shape.

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 tight sentences with the scope and platform set front-loaded and the update semantics immediately after. No filler or redundancy.

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?

For a mutation tool with full annotation coverage, a complete schema and no output schema, the description supplies the key behavioral facts an agent needs: partial update, auth scope, and platform immutability. Only error/conflict behavior remains undocumented, a minor gap.

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 all five parameters are already documented in the schema, which sets the baseline at 3. The description adds only the 'platform cannot be changed here' constraint, which is not a parameter in the schema, so it contributes little parameter-level meaning.

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 ('Update') and resource ('posting account'), scoped to the platforms TikTok, Instagram and YouTube. The verb cleanly separates it from create/get/list/delete siblings, though no sibling is named to differentiate from other update-style 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 description implies usage context via 'the authenticated user is allowed to manage' and constrains editing to supplied fields only, but it never states when to prefer this tool over get-account-tool or create-account-tool, nor any explicit prerequisite or exclusion. Usage is inferable rather than stated.

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