Upgrade Info

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

The description adds context beyond the annotations by explaining error behavior: 'on invalid, missing, or malformed input this tool never raises a protocol error — it returns {"error": ...}'. It also reinforces the annotations by stating 'Every call is read-only and idempotent', and adds the practical implication of safe retrying. This gives the agent a complete behavioral model.

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 compact and front-loaded: the main purpose is stated immediately, followed by required parameter info, return shape, error handling, and safety guarantees. Every sentence adds value, with no redundant or filler content.

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 tool with no parameters and an output schema, the description covers all essential aspects: what it explains, what the response contains ('message', 'how', 'free_tier'), how errors are handled, and its read-only/idempotent nature. Combined with the annotations and schema, the agent has everything needed to use it correctly.

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?

With zero parameters, the description explicitly notes 'Takes no arguments.' This directly matches the empty properties schema and removes any ambiguity. Since the baseline for 0 params is 4, the explicit confirmation and clarity push it to 5.

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 opens with a specific verb and scope: 'Explain how to unlock full personas, paid skills, and kits.' It clearly states what the tool does and covers a distinct informational niche compared to sibling tools like get_full_skill or list_kits, making it easy for an agent to select when a user asks about upgrade paths.

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?

The phrase 'FREE.' and the explanation of what the tool returns ('describing the upgrade path and what stays free') give clear context for when to invoke it—when users ask about unlocking paid features or free-tier benefits. It does not explicitly name alternatives or exclusions, but the purpose is obvious enough that an agent can infer appropriate usage.

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