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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds real value beyond that: the exact serialization format (wallet.yaml), the specific data classes included, and a privacy guarantee ('Never card numbers') that an agent could not infer from structured fields.

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?

A single compact sentence with the artifact front-loaded before the contents list, and the security caveat placed last for emphasis. It is a sentence fragment, but nothing is wasted and no sentence is filler.

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 zero-parameter, read-only tool with an output schema, the description covers what an agent needs to select it. Minor gaps remain — where the file is written and whether it overwrites an existing wallet.yaml — but these are secondary given the output schema and annotations.

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 tool takes zero parameters, so the baseline is 4. The description correctly adds nothing extraneous about inputs and instead spends its words on output content.

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 action and artifact: exports the saved wallet as a wallet.yaml file. It also enumerates the exported contents (card ids, picks, activations, memberships, cap usage, bonus progress), which makes the resource concrete. It doesn't explicitly distinguish itself from list_wallet or import_wallet, so sibling differentiation relies on the name.

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?

Usage is only implied: naming 'the earnrate command line and earnrate.dev' as consumers hints at when you'd export (to move data into those tools). There is no explicit when-to-use/when-not, and no mention of list_wallet as the read-only alternative or import_wallet as the inverse operation.

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