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

With no annotations, the description carries the burden. It discloses that authentication is required and notes the tool's motivational intent ('creates urgency and drives engagement'). However, it does not explicitly state whether this is a read-only operation or any side effects, though 'Calculate' implies no mutation. The absence of such detail limits transparency.

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 sentences, front-loaded with the core purpose. The final sentence combines 'Creates urgency and drives engagement' with 'Requires authentication,' which is slightly less structured. Overall it is concise and avoids unnecessary verbosity, though the engagement phrase is somewhat marketing-oriented.

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?

The tool has no output schema, but the description explains the high-level result (shows number of actions needed). It mentions authentication and optional parameters indirectly through the schema. For a calculation tool, this is sufficient for an agent to select and invoke it, though edge cases or error behaviors are not covered.

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 description coverage is 100%, so the baseline is 3. The description adds context about what actions mean (purchases, reviews, referrals) but does not add meaning beyond the schema for userId, brandId, or targetPerkId. The schema already explains those parameters sufficiently.

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's purpose: 'Calculate the fastest path to a user's next attainable reward.' It specifies the verb (calculate), resource (path to reward), and adds details about showing action counts. This distinguishes it from siblings like claim_reward or my_rewards, which focus on different actions.

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 description implies when to use the tool (to motivate users toward a goal) and states a prerequisite (requires authentication). However, it does not explicitly mention alternatives or when not to use it, though the schema notes optional parameters for specific or best goals. This provides clear context but no exclusionary guidance.

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