List NFC readers and cards

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 which data is exposed (readers, mappings, last-scan UID) but does not disclose whether results are cached, how many MiSTers are covered, or what happens if no card has been scanned — modest added value.

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 no filler, and the most useful cross-reference (map_nfc_card UID default) is placed at the end where it is memorable. The grammatical fragment structure is slightly awkward but costs little space.

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?

An output schema exists, so explaining return values is redundant — yet that is essentially all the description does, leaving the action verb and usage context unaddressed. For a simple read tool that is borderline adequate, but the definition doesn't fully pull its weight alongside the structured fields.

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 one parameter and 100% schema description coverage, the schema already explains 'host' (MiSTer name from get_status, omit when a ref supplies it). The description contributes nothing further about the host parameter, 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?

The sentence is a noun-phrase fragment that enumerates what the tool surfaces (NFC readers, card-to-game mappings, last scanned card) but never states the verb — the listing action is only inferable from the title. It does distinguish content from siblings implicitly and name-checks map_nfc_card, but an agent reading the description alone has to guess that this is a read/list 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?

There is no explicit when-to-use or when-not-to-use guidance. The parenthetical about map_nfc_card defaulting to the last scanned card's UID hints at a sequencing relationship, but it is oblique and doesn't tell the agent when to call list_nfc versus write_nfc_card or map_nfc_card.

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