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

Annotations only say readOnlyHint=false and destructiveHint=false. The description goes well beyond them: it discloses the auth class required, that the write is an upsert keyed by slug (so calling it with an existing slug retitles rather than creating), the downstream state dependency ('A pack with no price grants nothing'), and the economic term ('You keep 80% of each pack sale').

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?

Front-loaded with the auth constraint and the core action, then the parameters, then the follow-on workflow — a sensible ordering and no filler. It is dense, with several clauses packed into one sentence, which costs a little readability but not correctness.

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 3-param mutation with no output schema and thin annotations, the description covers prerequisites, constraints, downstream steps and economics. The one omission is what the call returns (the description implies a pack id via 'ref:<pack id>' but never states it), which an agent needs to chain into product_set.

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 0%, so the description carries the full burden, and it does: slug charset and length (lowercase, digits, - _, ≤60), title ≤120, description ≤2000. All three parameters gain validation constraints that exist nowhere in the schema.

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?

States a specific verb and resource ('Create — or retitle, keyed by slug — a PACK of items you own'), and the upsert semantics distinguish it from a plain creator. The follow-up tools (pack_items_set, product_set) make its role in the flow unambiguous relative to siblings like pack_get and product_set.

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?

Gives the auth prerequisite explicitly ('Requires a JWT (never an rk_ key)'), names the alternative tools and the conditions that select them ('Then add items with pack_items_set and price the pack with product_set'), and warns that an unprimed pack 'grants nothing'. Nothing about when to reach for this tool is left to inference.

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