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

Annotations declare destructiveHint=true, idempotentHint=true, but the description adds substantial context the annotations cannot: the personal-account-only scope (no team workspaces), per-Instagram-account scheduled Note semantics, duplicate rejection, and the needsNewTime result on a passed send time.

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?

Purpose and platform list are front-loaded, and most sentences carry operational weight. However, 'Only change the account the writer asked for' largely repeats the earlier per-account sentence, adding mild 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 that is destructive but idempotent, the description covers preconditions, failure modes, account source alternatives and the reschedule-on-passed-time path. Since an output schema exists, return values need no further explanation, leaving no meaningful gaps.

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 both parameters are already documented in the schema, including the accountId source lists. The description reinforces the accountId origin but adds little syntax or format detail beyond what the structured fields provide, so the baseline 3 applies.

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+resource (change the sending account of an already scheduled Note) and enumerates supported platforms. It is clearly distinguishable from siblings like amend_scheduled_item_content, reschedule_scheduled_item and cancel_scheduled_item.

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?

Explicitly routes to list_social_accounts and list_instagram_destinations for the accountId, states the precondition ('works only while the Note has not started sending'), and describes refusal cases (out-of-plan account, duplicate). It also covers the needsNewTime rescheduling path.

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