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

Annotations already declare the mutation profile (readOnlyHint=false, idempotentHint=true, destructiveHint=false), so safety is covered. The description usefully adds that this changes persistent global 'active billing context' state rather than a per-call parameter, but it does not say what happens on an invalid or unknown slug, nor whether the change persists 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 short sentences with the effect front-loaded before the accepted input formats, and no filler. The format examples partly duplicate the schema but stay brief enough to not be 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 one-parameter state-toggle tool with no output schema and full annotation coverage, the description gives an agent enough to call it correctly. Remaining gaps are minor: error behavior on bad input and confirmation of the resulting active context.

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 parameter is fully documented with the same slug/team-ID examples. The description adds no format, validation, or defaulting detail beyond what the schema already provides, 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 and resource ('Set the active billing context'), which tells an agent exactly what changes. It is clearly distinguishable from siblings like account_list or account_setup, though it never explicitly names or contrasts those siblings.

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 only implied: the agent infers this is the way to change which account subsequent billing operations apply to. There is no explicit when-to-use, no prerequisite (e.g. must the slug already exist), and no guidance on when account_setup or account_preferences is the better choice.

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