Embers: Tabletop RPG Toolkit

Update a session

play_update_session

Idempotent

Update a session by id. Use this to append session notes, change the date, rename, or tag the session with the Imagine adventure it belongs to (imagineAdventureId — valid ids come from the campaign's imagineAdventures list on play_get_campaign; null untags). Only the fields you supply are sent. Caller must be the session's owner, an admin with Admin Mode on, or the campaign's GM (its owner or an accepted gamemaster); players get 403. REQUIRES baseUpdatedAt: copy updatedAt from a fresh play_get_session read; a stale or fabricated value is rejected with OUT_OF_SYNC and nothing is written.

Input Schema

Name	Required	Description
`id`	Yes	Mongo `_id` of the session to update.
`date`	No	Session date in `dd/mm/yy` format.
`name`	No	Session name / title.
`image`	No
`status`	No
`dateDay`	No
`summary`	No	Short session summary. Max 150 characters.
`dateYear`	No
`dateMonth`	No
`battlemaps`	No
`characters`	No
`description`	No	Session body / notes / recap. Markdown supported.
`baseUpdatedAt`	Yes	REQUIRED proof that you are working from the latest version: copy the `updatedAt` value verbatim from a FRESH read of this exact record (use the matching get tool first). Values from memory, from an earlier conversation, or guessed timestamps are rejected with OUT_OF_SYNC and nothing is written. After a successful update, the response carries the new `updatedAt` — use that for any follow-up write.
`sessionImages`	No
`imagineAdventureId`	No	Imagine adventure this session is part of. Must be one of the ids in the campaign's `imagineAdventures` list (see play_get_campaign); adventures are linked to the campaign with imagine_link_adventure_to_campaign. Pass null to untag the session. Omit to leave unchanged.

Output Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

Changed18 schema fields changedSep 25, 2026

addedInput schema / $schema

Added value: +"http://json-schema.org/draft-07/schema#"

addedInput schema / additionalProperties
```
Added value: +{}
```

addedInput schema / properties / baseUpdatedAt

Added value: +{
+  "description": "REQUIRED proof that you are working from the latest version: copy the `updatedAt` value verbatim from a FRESH read of this exact record (use the matching get tool first). Values from memory, from an earlier conversation, or guessed timestamps are rejected with OUT_OF_SYNC and nothing is written. After a successful update, the response carries the new `updatedAt` — use that for any follow-up write.",
+  "minLength": 1,
+  "type": "string"
+}

addedInput schema / properties / battlemaps

Added value: +{
+  "items": {
+    "additionalProperties": {},
+    "properties": {
+      "_id": {
+        "description": "Mongo `_id` reference (24-character hex string).",
+        "minLength": 1,
+        "type": "string"
+      },
+      "visibleToPlayers": {
+        "type": "boolean"
+      }
+    },
+    "type": "object"
+  },
+  "type": "array"
+}

addedInput schema / properties / characters

Added value: +{
+  "items": {
+    "description": "Mongo `_id` reference (24-character hex string).",
+    "minLength": 1,
+    "type": "string"
+  },
+  "type": "array"
+}

addedInput schema / properties / date

Added value: +{
+  "description": "Session date in `dd/mm/yy` format.",
+  "pattern": "^(\\d{1,2})\\/(\\d{1,2})\\/(\\d{2})$",
+  "type": "string"
+}

addedInput schema / properties / dateDay

Added value: +{
+  "maximum": 31,
+  "minimum": 1,
+  "type": "integer"
+}

addedInput schema / properties / dateMonth

Added value: +{
+  "maximum": 12,
+  "minimum": 1,
+  "type": "integer"
+}

addedInput schema / properties / dateYear

Added value: +{
+  "maximum": 9007199254740991,
+  "minimum": -9007199254740991,
+  "type": "integer"
+}

addedInput schema / properties / description

Added value: +{
+  "description": "Session body / notes / recap. Markdown supported.",
+  "type": "string"
+}

addedInput schema / properties / id

Added value: +{
+  "description": "Mongo `_id` of the session to update.",
+  "minLength": 1,
+  "type": "string"
+}

addedInput schema / properties / image
```
Added value: +{
+  "type": "string"
+}
```

addedInput schema / properties / imagineAdventureId

Added value: +{
+  "anyOf": [
+    {
+      "minLength": 1,
+      "type": "string"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "description": "Imagine adventure this session is part of. Must be one of the ids in the campaign's `imagineAdventures` list (see play_get_campaign); adventures are linked to the campaign with imagine_link_adventure_to_campaign. Pass null to untag the session. Omit to leave unchanged."
+}

addedInput schema / properties / name

Added value: +{
+  "description": "Session name / title.",
+  "minLength": 1,
+  "type": "string"
+}

addedInput schema / properties / sessionImages

Added value: +{
+  "items": {
+    "additionalProperties": {},
+    "properties": {
+      "name": {
+        "type": "string"
+      },
+      "url": {
+        "type": "string"
+      },
+      "visibleToPlayers": {
+        "type": "boolean"
+      }
+    },
+    "type": "object"
+  },
+  "type": "array"
+}

addedInput schema / properties / status

Added value: +{
+  "enum": [
+    "pending",
+    "active",
+    "completed",
+    "cancelled"
+  ],
+  "type": "string"
+}

addedInput schema / properties / summary

Added value: +{
+  "description": "Short session summary. Max 150 characters.",
+  "maxLength": 150,
+  "type": "string"
+}

addedInput schema / required

Added value: +[
+  "id",
+  "baseUpdatedAt"
+]

First observedSep 21, 2026

TDQS

A4.5/5.0

Behavior5/5

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

Adds substantial behavior beyond the annotations: partial-update semantics ('Only the fields you supply are sent'), the authorization matrix (owner / Admin Mode admin / campaign GM), the 403 outcome for players, and the optimistic-concurrency contract (stale or fabricated baseUpdatedAt -> OUT_OF_SYNC with nothing written). The annotations only give idempotent/non-destructive/openWorld flags; this description supplies the operational contract they omit.

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?

Dense but front-loaded: the core action and its editable fields come first, then scoping, then auth, then the concurrency requirement. Every sentence carries load, though the back half is a long run of parenthetical qualifiers that could be tightened without losing meaning.

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?

An output schema exists, so return format needn't be described, and annotations cover the safety profile; the description completes the picture with partial-update behavior, authorization, and the concurrency handshake for follow-up writes. It is not fully complete only because several of the 15 parameters remain undocumented in both description and schema.

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 47% (below 50%), so the description needs to carry weight, and it does for the two hardest fields: baseUpdatedAt (why it exists, where to copy it from, what a stale value triggers) and imagineAdventureId (valid id source, null-untag, omit-unchanged). However, roughly half the parameters (image, status semantics, battlemaps, characters, sessionImages, the date* fields) get no added meaning beyond the schema. Partial compensation justifies a 3.

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+resource and then enumerates the concrete capabilities (append notes, change date, rename, tag with imagineAdventureId), which lets an agent distinguish it from create_session / delete_session / get_session without opening a schema. The `by id` scoping and the tagged-adventure example are unambiguous.

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 when to use it (the four enumerated edits), what it requires (fresh read of the record for baseUpdatedAt), which tools supply needed data (play_get_session, play_get_campaign's imagineAdventures), null-vs-omit semantics for untagging, and who is denied ('players get 403'). Nothing material is left to inference.

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

All Embers: Tabletop RPG Toolkit 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?