System Prompt

Every prompt mutation creates a new version in the history and atomically updates the agent's systemPrompt and activePromptId. This lets you audit changes and restore earlier versions.

Consejo

Calling PATCH /v1/agents/{agentId} with a systemPrompt field also creates a version automatically — the prompt is always versioned.

Get Active Prompt

GET https://api.platica.mx/v1/agents/{agentId}/prompt

URL parameters

Parameter	Type	Description	Required
`agentId`	string	Unique identifier of the agent	✓

Response

{
  "systemPrompt": "Eres un asistente de soporte experto...",
  "activePromptId": "j8sl3KdQF1IBpRtoSWtR",
  "lastUpdate": "2026-05-28T06:14:21.000Z"
}

Response fields

Field	Description
`systemPrompt`	Text of the active prompt
`activePromptId`	ID of the active version in the history
`lastUpdate`	Last update date in ISO 8601 format

Write Prompt

Overwrites the prompt with content and creates a new entry in the history.

POST https://api.platica.mx/v1/agents/{agentId}/prompt

URL parameters

Parameter	Type	Description	Required
`agentId`	string	Unique identifier of the agent	✓

Request body

{
  "content": "Eres un asistente de soporte para una tienda de electrónica...",
  "details": "Rewrite tras lanzamiento del producto X"
}

Parameter	Type	Description	Required
`content`	string	Full content of the system prompt	✓
`details`	string	Descriptive note about the change, stored with the version (≤ 1000 chars)	—

Response

{
  "status": "success",
  "message": "Agent system prompt written successfully",
  "data": {
    "activePromptId": "id45iLWReNWPfEGkAbFv",
    "systemPrompt": "Eres un asistente de soporte...",
    "contentLength": 4321
  }
}

Edit Prompt

Replaces a fragment of the current prompt. By default it tries an exact match, then a fuzzy match (with whitespace normalized). If useRegex is true, oldText is interpreted as a regular expression.

PATCH https://api.platica.mx/v1/agents/{agentId}/prompt

URL parameters

Parameter	Type	Description	Required
`agentId`	string	Unique identifier of the agent	✓

Request body

{
  "oldText": "tono formal",
  "newText": "tono cercano y conversacional",
  "useRegex": false
}

Parameter	Type	Description	Required	Default
`oldText`	string	Text to find (must be unique unless `useRegex: true`)	✓	—
`newText`	string	Replacement text (may be empty to delete)	✓	—
`useRegex`	boolean	If `true`, `oldText` is interpreted as a regular expression	—	`false`

Response

{
  "status": "success",
  "message": "Agent system prompt edited successfully",
  "data": {
    "activePromptId": "8Xdjb0VjgIq35mzmt1wu",
    "systemPrompt": "Eres un asistente de soporte...",
    "matchesFound": 1,
    "replacementsMade": 1,
    "editType": "exact"
  }
}

editType can be "exact", "fuzzy", or "regex" depending on how the match was resolved.

Common errors

Status	Cause
`400 Multiple matches`	`oldText` appears more than once; be more specific or use `useRegex: true`
`400 No match found`	Neither the exact nor the fuzzy match located the text
`400`	The agent has no previous `systemPrompt` to edit

Notes

The full version history is read via /v1/agents/{agentId}/prompt/versions .
details is optional but recommended: it is stored on each version as a descriptive note about the change and appears in the version listing.
To manage the prompt of a connected sub-agent, use /v1/agents/{agentId}/subagents/{subagentId}/prompt — verify first that the connection exists.

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