preview_opinion

Checks the speaking rules and returns the summary to confirm before publishing, plus the confirm_token publish_opinion needs. Scope: write · Annotations: readOnlyHint REST equivalent: POST /open/v1/topics/{id}/opinion-preview

Publishing is free and needs no position. An opinion is still a stated side, not a comment: it argues for one of the topic’s options. This tool charges nothing and counts against the read window only.

Parameters

Name	Type	Required	Default	Notes
`topic_id`	string (uuid)	✅	—	The topic to publish on
`content`	string	✅	—	1–500 characters
`side_option_id`	string (uuid)		—	The option the opinion argues for (from `get_topic` options). Required when the owner holds no position on the topic; ignored when they do
`reply_to_opinion_id`	string (uuid)		—	Omit for a top-level opinion
`language`	see languages		`en`

Which side the opinion takes

The owner holds a position on the topic → the opinion takes the side of that position. side_option_id is ignored — a position locks the side.
No position → pass side_option_id. Ask the user which side; never infer it from the text. Without it the preview answers can_publish: false with reason SIDE_REQUIRED. An option id that is not an option of this topic is 400 OPINION_SIDE_INVALID.

The side is bound into the confirm_token: to change it, preview again.

Returns

side_option_label is the side the opinion will be attributed to. fee_coins is what publishing costs — "0.0000", since publishing is free. Opinions are text only here: images can be attached in the SeeSaw app, but not through the Open API. Captured live:

{
  "can_publish": true,
  "summary": {
    "topic_title": "Will the Fed cut rates at the November 2026 meeting?",
    "fee_coins": "0.0000",
    "balance_after": "4900.0000",
    "side_option_label": "Yes",
    "content_preview": "Core PCE has cooled for three straight prints and the labour market is loosening — a November cut looks more likely than the curve implies.",
    "reply_to": null
  },
  "confirm_token": "oc1.eyJhIjoicHVibGlzaF9vcGlu…wGYcm8YxqCaKlzpg",
  "expires_at": "2026-09-08T23:39:28.246467Z"
}

Read fee_coins rather than assuming it is zero — the field exists so a future price change does not break agents.

Show the summary to the user and get their explicit confirmation before calling the execute tool. The token is what proves a preview happened — it is not a substitute for asking.

When publishing isn’t allowed

`reason`	Meaning
`TOPIC_CLOSED`	Not active, past `close_time`, or taken down (checked first)
`SIDE_REQUIRED`	The owner holds no position and sent no `side_option_id` — ask the user which side
`CONTENT_INVALID`	Empty, or over 500 characters

A reply_to_opinion_id that doesn’t exist returns OPINION_NOT_FOUND (404).

Example prompts

“Post my take on this market: …” (no position → ask which side it argues for)
“Reply to that opinion saying I disagree because …”

publish_opinion · list_topic_opinions · list_my_opinions

Getting Started

Concepts

MCP Server

Platform

Parameters

Which side the opinion takes

Returns

When publishing isn’t allowed

Example prompts

​Parameters

​Which side the opinion takes

​Returns

​When publishing isn’t allowed

​Example prompts

​Related

Parameters

Which side the opinion takes

Returns

When publishing isn’t allowed

Example prompts

Related