Postfjord

Update email draft

postfjord_update_campaign

DestructiveIdempotent

Changes the subject, preheader, name, blocks or audience of a draft email; only send what changes. The audience is tags (tag names), segment (a saved segment) or everyone: true, one of the three. blocks replaces all blocks: keep a block as it is with { "type": "keep", "id": "..." } using ids from postfjord_get_campaign. A block written back with its id stays in its background box. Only a draft can change; a scheduled email must be unscheduled first with postfjord_cancel_campaign. Automation emails are changed in the app.

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": {
      "campaignId": "<campaignId>"
    },
    "name": "postfjord_update_campaign"
  }
}

Input Schema

Name	Required	Description
`name`	No	An internal name, only the team sees it.
`tags`	No	Send only to contacts with any of these tags, by tag name.
`blocks`	No	Replaces all blocks, top to bottom.
`segment`	No	Send only to this saved segment, by name or id.
`subject`	No	The new subject line.
`everyone`	No	Send to everyone who said yes again.
`preheader`	No	The line inboxes show after the subject.
`campaignId`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

Changed4 schema fields changedOct 28, 2026
- addedInput schema / properties / blocks / description
```
Added value: +"Replaces all blocks, top to bottom."
```
- addedInput schema / properties / name / description
```
Added value: +"An internal name, only the team sees it."
```
- addedInput schema / properties / preheader / description
```
Added value: +"The line inboxes show after the subject."
```
- addedInput schema / properties / subject / description
```
Added value: +"The new subject line."
```
First observedOct 26, 2026

TDQS

A4.5/5.0

Behavior4/5

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

Annotations already declare destructiveHint=true and idempotentHint=true, and the description adds real context beyond them: blocks is a full replacement, unchanged blocks must be echoed back as {type:keep,id} to preserve their background box, and ids must come from postfjord_get_campaign. It does not address permissions or what the response contains, which is the only remaining gap.

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

Conciseness4/5

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

The opening sentence is front-loaded with purpose and the partial-update rule, and every following sentence carries a distinct constraint (audience choice, keep blocks, draft-only, automation exclusion). It is dense and slightly run-on but has no filler.

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

Completeness4/5

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

For a destructive partial-update tool with no output schema, the description covers the mutation scope, the block replacement trap, and the state preconditions (draft, not scheduled, not automation). Only the return value after a successful update is left unstated, which is minor here.

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

Parameters4/5

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

Schema coverage is 88%, so the baseline is 3, but the description adds semantics the schema cannot: the audience is exactly one of tags, segment, or everyone:true, and the keep-block/id provenance rule for blocks. These are the two parameters most likely to be misused, and both are clarified.

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 plus resource and enumerates the mutable fields: subject, preheader, name, blocks, audience of a draft email. It also scopes the resource as a draft, which separates it cleanly from postfjord_schedule_campaign and postfjord_create_draft in the sibling list.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

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

Explicitly says only a draft can be changed and routes the agent to postfjord_cancel_campaign when the email is scheduled, and to the app for automation emails. It also states the partial-update rule ('only send what changes'), so the agent knows not to resend unchanged fields.

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

All Postfjord 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?