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

Goes well beyond the annotations by disclosing credential requirements (Last Price credential with billing write scope) and a prerequisite that causes hard failure (claimed workspace; sandbox key → 403). The annotation set already flags destructive/idempotent, and the description adds the operational constraints that actually determine whether the call succeeds.

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?

Front-loaded with the action and the field list, then constraints. Dense and mostly waste-free, though the trailing auth/workspace sentences are packed together without structural separation, making them easy to skim past.

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 with no output schema, it covers the fields, immutable properties, permissions, and failure modes. It does not describe what a successful response returns or how nulls on credits/rollover_credits are interpreted (clear vs no-op), which matters for a partial-update tool.

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 only 14%, so the description must compensate and largely does: it maps the status enum values to human intents (activate/inactive/archive) and names the mutable fields. It stops short of clarifying the distinction between credits and rollover_credits (both nullable) or price units, leaving some ambiguity.

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 ('Change a credit bundle') and then enumerates exactly which attributes are mutable (status, name, description, price, credits, rollover) plus what each status value means. Clearly distinguishable from create_credit_bundle_plan and list_credit_bundle_plans.

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 operating context: code and currency are immutable, and the tool is 'Early access'. It does not explicitly name an alternative tool or a when-not-to-use condition, so it falls short of a 5, but the usage envelope is unambiguous.

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