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

Annotations (readOnlyHint, idempotentHint, non-destructive) already cover the behavioral profile, and the description adds no contradictory side effects or permissions requirements. It neither enhances nor undermines transparency, so a neutral 3 is appropriate given the annotation coverage.

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 core sentence is concise, but the description contains redundant repetition ('Returns the loyalty points...' twice) and includes a misplaced 'Guidance:' and 'context: user_id' suffix that disrupts structure and adds noise without value.

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 simple read-only getter with a single parameter, the description sufficiently explains the operation and input. No output schema is present, but for such a straightforward retrieval, the provided information is complete enough for an agent 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?

The only parameter, user_id, has a schema description ('Unique ID of the user') providing full coverage (100%). The description repeats 'context: user_id' but adds no additional semantic meaning beyond the schema, so the baseline score for full coverage is maintained at 3.

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 it 'Returns the loyalty points details of a user', which specifies the verb and resource. It distinguishes from shop_update_loyalty among siblings, but the duplicate phrasing and the odd 'Guidance:' and 'context: user_id' appendix create slight confusion, preventing a 5.

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 usage is to retrieve loyalty points for a user, but it does not explicitly state when to use it over other getter tools or any prerequisites. The context is self-evident, but no direct guidance or alternative contrast is provided.

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