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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered; the description adds useful behavioral detail beyond that: newest-first ordering and the set of transaction types returned. It does not discuss pagination or the maximum result window (limit cap of 50), which is the only notable omission.

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?

Two tight sentences: purpose and ordering first, then the disambiguating alternatives. Every clause earns its place and nothing is repeated from the schema or annotations.

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 listing with no output schema, the description supplies scope, ordering, and transaction categories, which is nearly everything an agent needs. It stops short of describing the per-transaction fields (amount, timestamp, source) an agent might present to a user.

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 100% schema description coverage on the single `limit` parameter, the schema already carries the semantics (1-50, default 10). The description adds nothing about result count or truncation, so the baseline of 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?

States a specific verb and resource ('List the user's recent credit transactions') and enumerates the transaction kinds (spend/refund/grant) plus ordering. It explicitly names the sibling tools that cover adjacent needs, so an agent can distinguish it without opening any schema.

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 explicit triggers ('where their credits went', 'spending history', 'verify a charge/refund') and routes the alternative cases to `popcraft_balance` for current balance and `popcraft_show_plans_and_credits` for plans/top-ups. Both when-to-use and when-to-use-something-else are covered.

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