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

Beyond annotations (readOnlyHint, idempotentHint), the description discloses the error handling behavior: it never raises a protocol error but returns an error object. This adds valuable behavioral context not captured in structured annotations.

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 moderately long but well-structured: starts with core purpose, then provides an example, usage notes, and error behavior. Every sentence adds value. A slight trim could make it more concise, but it is still efficient.

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?

Given the presence of an output schema, the description provides an example return shape and covers error returns. It also explicitly states when to use and what it does. No gaps remain for an agent to effectively invoke the 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 100% with clear descriptions for both parameters. The description adds a example input and repeats that skill_name selects the skill, but does not significantly extend the parameter meaning. Baseline 3 is appropriate.

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 loads one paid skill's complete instructions from a product, distinguishes it from get_free_skill and get_full_product, and provides a typical input/output example. This makes the purpose specific and distinct from siblings.

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?

Explicitly says 'Use after preview_product has shown the skill list and the caller wants one specific paid skill.' It also tells when not to use: 'Not for the free gateway skill... and not for every skill at once.' Names alternative tools (get_free_skill, get_full_product). This is excellent guidance.

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