Switch the active billing account

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

With only destructiveHint=false in annotations, the description carries most of the load and does well: it discloses the accepted input forms, that it resolves to a name/id on success, and that a non-matching id yields an error. It stops short of stating auth requirements or whether the switch persists across sessions, so not a full 5.

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 tight sentences, front-loaded with the effect, followed by the sequencing guidance and the return behavior. No filler; every sentence earns its place.

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 single-parameter switch tool with no output schema, the description covers effect, prerequisites, input forms, and success/failure outcomes. Nothing an agent needs to invoke it correctly 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 coverage is 100% and the single id parameter is fully documented in the schema, including the full-UUID-or-unique-prefix semantics and the accounts_list pointer. The description's mention of the same details adds little beyond what the schema already states, so 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 (Set) and resource (active billing account that project commands operate on), and positions itself clearly against siblings accounts_list and accounts_create. An agent can distinguish this from projects_use and config_use without opening a 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?

Explicitly names the precondition ('after login'), the condition ('when you belong to more than one account'), and the downstream tools that depend on it ('projects_list', 'projects_create', 'projects_use'). It also routes to accounts_list for id discovery, leaving little to inference.

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