Paddock Cards

Preview a card

preview_card

Read-onlyIdempotent

Show a prepared card’s finished surfaces before payment when preview_available is true. Optional, never required to buy. Returns images and their order revision, plus preview_url for clients that need a browser. Preview again after changes. This does not change, charge or mail the order.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "order_id": "<order_id>",
      "order_access_token": "<order_access_token>"
    },
    "name": "preview_card"
  }
}

Input Schema

Name	Required	Description	Default
`faces`	No	Surfaces to render; omission means both. Outside/inside are front/back for postcards and flat cards, or cover/inside for folded cards.	both
`card_id`	No	ID from this order.cards[].id. Required when the order has more than one card; omit to preview its only card.
`order_id`	Yes	Parent order.id returned by prepare_order, revise_order or read_order. Use the matching private token.
`expected_revision`	No	Parent order.revision returned by prepare_order, revise_order or read_order. If supplied, a mismatch fails with CONFLICT; omission previews the current revision. Preview again after changes.
`order_access_token`	Yes	Exact private order_access_token returned by prepare_order or revise_order for this order. Keep it private and never invent one.

Output Schema

Name	Required	Description	Default
`ok`	Yes
`data`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

Changed5 schema fields changedOct 29, 2026

changedInput schema / properties / card_id / description

Previous value: -"Required when the order has more than one card."New value: +"ID from this order.cards[].id. Required when the order has more than one card; omit to preview its only card."

changedInput schema / properties / expected_revision / description

Previous value: -"Fail with CONFLICT if the order revision differs, so the buyer approves what they saw."New value: +"Parent order.revision returned by prepare_order, revise_order or read_order. If supplied, a mismatch fails with CONFLICT; omission previews the current revision. Preview again after changes."

addedInput schema / properties / faces / description

Added value: +"Surfaces to render; omission means both. Outside/inside are front/back for postcards and flat cards, or cover/inside for folded cards."

changedInput schema / properties / order_access_token / description

Previous value: -"The private capability returned by prepare_order. Never invent one."New value: +"Exact private order_access_token returned by prepare_order or revise_order for this order. Keep it private and never invent one."

addedInput schema / properties / order_id / description

Added value: +"Parent order.id returned by prepare_order, revise_order or read_order. Use the matching private token."

AddedOct 29, 2026

TDQS

A4.3/5.0

Behavior4/5

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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety bar is low; the description still adds that it neither changes, charges nor mails the order, and that it returns images plus an order revision and a preview_url for browser clients. The repetition of read-only semantics is mild but the return-shape and re-preview guidance add real value.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Four short sentences, front-loaded with the precondition and the action, then returns, then the re-preview rule, then the non-mutation guarantee. No sentence is filler.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

An output schema exists so return values need no prose expansion, and annotations cover the safety profile. The description still supplies the preview_available gate, the post-change re-preview rule and the non-mutation guarantee, leaving nothing an agent needs in order to call it correctly.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so faces, card_id, expected_revision and the token are already fully documented in the schema. The description adds only the indirect hint 'Preview again after changes,' which echoes expected_revision without new syntax or format detail — baseline 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource: show a prepared card's finished surfaces, scoped to pre-payment and the preview_available precondition. An agent can distinguish this from compose_private_card, prepare_order or pay_order 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.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives clear usage context — call before payment when preview_available is true, call again after changes — and an explicit exclusion: 'Optional, never required to buy.' It does not name an alternative sibling for any scenario, which keeps it short of a 5.

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

All Paddock Cards tools Inspect

Try in Browser

One endpoint for every MCP toolRayrun runs every MCP server behind one URL and holds the credentials. Each call is decided per client, tool, and argument, then recorded.ray.runAd

Glama MCP Gateway

Add one secure layer between your agents and this server.

Resources

Need Help?