Plan a subscription lifecycle change

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

Beyond the annotations (readOnlyHint, idempotentHint, destructiveHint false), the description adds specific behavioral details: 'nothing is executed, no Partner Center credentials are used, and no network call is made — it is a lookup over the bundled scenario pack.' It also explains the internal plan structure (reads subscription first, states precondition, performs, confirms). This significantly exceeds annotation-only information.

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?

The description is three well-structured sentences. The first sentence states the core purpose and operations. The second gives usage and alternatives. The third clarifies constraints and return structure. Every sentence adds value, and the content is front-loaded with the primary function.

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?

Despite the tool's complexity, the description covers the full context: what it does, how to choose it (with alternatives), safety/profile (no execution, no credentials, no network), the return shape ({ goal, steps[], notes[] }), and how to proceed (pass scenarioId to pc_generate_call or pc_get_scenario). The output schema is also present, so the description is thoroughly 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?

The input schema already provides 100% coverage with descriptions for both parameters, including the enum values and the optional customerId placeholder substitution. The tool description itself does not add meaning beyond the schema—it mentions the return steps but not the parameters. Baseline of 3 is appropriate when schema fully documents parameters.

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 clearly states the tool returns an ordered call sequence for one subscription lifecycle change, and enumerates the specific operations (increase-seats, decrease-seats, upgrade, etc.). It explicitly distinguishes from sibling tools by pointing to pc_explain_lifecycle for choosing an operation, pc_plan_purchase for new purchases, and pc_plan_order_lifecycle for order-side planning, making the purpose unambiguous.

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?

It provides explicit guidance: 'Use pc_explain_lifecycle to find out WHICH operation is available; use this to find out HOW to run it.' It also clarifies planning-only nature and directs alternative tools for purchase and order lifecycle. The description even notes to pass a scenarioId to pc_generate_call for runnable code, giving clear next steps.

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