list_decks

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

With no annotations provided, the description carries the full burden of behavioral disclosure, and it does well by declaring 'Read-only' and the serial-call constraint, both of which are critical for an agent to know and are not apparent from the schema. The output format is documented via the output schema, so the description does not need to cover that. A minor gap is that it does not mention behavior such as empty results or error conditions, but these are less critical for a read-only zero-arg tool.

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 three short sentences, each with a distinct purpose: scope, safety, and invocation order. It is front-loaded with the primary purpose and contains no filler, redundancy, or extraneous detail.

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-argument listing tool with an output schema, the description is nearly complete: it states the action, the scope, the read-only nature, and the parallel-call constraint, giving an agent everything needed to invoke it safely. The only missing piece is explicit navigation of sibling tools, but the phrase 'deck names only' makes that distinction inferable.

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 input schema has zero parameters, so there is no parameter meaning for the description to add beyond what the schema provides. The 0-parameter baseline of 4 applies. Nothing is left undocumented, and no param-level elaboration is needed.

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 uses a specific verb ('List') and resource ('Anki deck names'), with the word 'only' clearly narrowing the scope to names rather than full deck objects. This cleanly separates the tool from siblings like list_deck_cards, get_card, and search_cards, which all operate on cards. The purpose is unambiguous and actionable.

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 provides a clear operational constraint ('Never call in parallel with other tools'), which is useful guidance for how to invoke the tool. However, it does not explicitly state when to choose this tool over its siblings, such as list_deck_cards for getting cards within a deck or search_cards for querying card content. The selection context is only implied through the phrase 'deck names only.

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