Write a game to an NFC card

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

Annotations already declare destructiveHint=true and idempotentHint=false, and the description reinforces this concretely ('Overwrites whatever the card held'). It also discloses behavior annotations cannot express: a blocking wait of up to a minute and a required human step. Return value detail is omitted, but an output schema exists so that is acceptable.

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?

Three short sentences, front-loaded with the action and its effect, followed by the destructive caveat and the human-in-the-loop timing. No filler and every sentence carries information an agent needs.

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 two-parameter, destructive hardware-writing tool with an output schema, the description covers purpose, side effect, precondition, and blocking behavior. The main omission is any mention of the map_nfc_card sibling, leaving the agent to infer which NFC operation to choose.

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 description coverage is 100%, and both parameters ('game' with ref format, 'reader' tied to list_nfc) are fully documented in the schema. The description adds no parameter-level meaning beyond that, so the baseline of 3 applies.

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 ('Write a game onto the NFC card') plus the physical target (reader attached to the game's MiSTer) and the outcome (tapping launches the game). It does not distinguish itself from the sibling map_nfc_card, which an agent could easily confuse with this operation.

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 clear operational context: ask the user to place the card first, and the call blocks up to a minute. That is actionable pre-call guidance. It stops short of saying when to prefer this over map_nfc_card or what to do if the card is absent at timeout.

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