Account switch

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

Annotations only declare readOnlyHint=false, openWorldHint=true, destructiveHint=false, so the description must carry the state-change story — and it does: later calls act as the new account, open Instagram tabs are reloaded, and the active-account case is a no-op. That side-effect disclosure is genuinely useful beyond the annotations, though it doesn't cover failure modes (e.g. not-logged-in accounts) or persistence across sessions.

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 a parenthetical cross-reference; the core action and its consequence on later calls are front-loaded, and nothing is wasted.

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 no-required-parameter state-switch tool with no output schema, the description covers the action, the source of the target id, the side effect on open tabs, and the no-op case. It could go slightly further on what the caller should do after switching or what happens on failure, but nothing essential is missing.

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 four parameters are already documented, including the userId/username alternative and the `instant` pacing rule. The description adds no parameter detail beyond restating that the target comes from account_info, so the baseline 3 is correct.

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 ('Switch') and resource ('the browser profile to another logged-in account'), and explicitly points to account_info for the account list, which is the adjacent sibling an agent would confuse it with. An agent can tell this apart from account_info without opening either schema.

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?

Gives clear preconditions (account must be logged in, id/username comes from account_info) and an explicit no-op case ('Switching to the active account is a no-op'), plus per-parameter usage rules for `instant`. It stops short of naming an alternative tool or stating when switching should be avoided.

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