janus_use_account

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

Annotations declare readOnlyHint=false, idempotentHint=true, destructiveHint=false, so the safety profile is already structured. The description adds genuinely useful side-effect context beyond that: the call reloads upstream tools and notifies the client, which tells an agent the tool list may change after invocation. It does not contradict the annotations.

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?

Three short clauses, front-loaded with the core action before the side effects and the scope note. No filler or restatement of the name. The parenthetical default could be phrased more tightly, but nothing is wasteful.

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 two-parameter state setter with no output schema, the description covers purpose, side effects, and the scope default. Annotations carry the safety profile. The remaining gap is account_id semantics and any failure behavior for an invalid account, which keeps it short of 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 0% for two parameters, so the description must compensate. It does explain the scope enum values and its default ('defaults to the broker bindingMode'), which is real added value. The required account_id gets no semantics at all – no format, no hint that it should come from janus_list_accounts – leaving half the surface undocumented.

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 states a specific verb and resource: 'Set the active account/identity.' That is unambiguous and an agent can distinguish it from janus_whoami (read current identity) or janus_list_accounts. It does not explicitly contrast itself with the closest sibling, janus_with_account, which is a scoped variant of the same idea.

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?

Usage is implied by the name and by 'Set the active account/identity' – an agent can infer this is the tool to call when switching identity. However, there is no explicit when-to-use guidance, no statement of when to prefer janus_with_account or janus_login instead, and no mention of prerequisites such as needing an existing authenticated session.

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