Diagram

What it does

When your agent uses it

• The user asks for a diagram
• Sequence diagram
• Architecture sketch
• Any visual that Mermaid can render — and whenever a diagram would clarify a complex flow

Example prompts

• “/diagram”

Requirements

• A credential in MC_API_TOKEN

Workflow steps

5 steps, taken from the first numbered list in SKILL.md.

1. 1Do not override Mermaid theme in source. Never use %%{init: {'theme':'dark'}}%%, %%{init: {'theme':'base', 'themeVariables': ...}}%%, YAML…
2. 2Use plain Mermaid syntax. Let Mission Control's viewer apply accent, surface, text, and border tokens from the active UI theme.
3. 3Read $MC_THEME. When it is dark, avoid near-black node/participant fills. When it is light, avoid near-white fills on white backgrounds.
4. 4Sequence diagrams: use default participant boxes — do not set actor background colors inline. Example
5. 5Flowcharts: prefer unstyled nodes (A[Step], B{Decision?}) over A["Step"]:::darkClass.

What it can do on your machine

Read from SKILL.md and the folder at commit 92b91d0. It shows what the files ask for, not the result of running them.

• Tool permissions

  Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

  From allowed-tools in the SKILL.md frontmatter.

• Runs code

  Shell commands in SKILL.md call:

  • curl
  • jq

  From the folder's file list and the shell code blocks in SKILL.md.

• Network

  No URLs in SKILL.md. Its commands use curl, which can reach the network depending on how they are called.

  From URLs in SKILL.md, links to its own repository left out.

• Credentials

  Names these keys or tokens, usually read from environment variables:

  • MC_API_TOKEN

  From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Diagram loads about 1.5k tokens when it runs. Until then it costs about 127 tokens; SKILL.md has 500 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it

~127

When it runs · the whole SKILL.md, loaded when a task matches

~1.5k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from AgentSystemLabs/mission-control at commit 92b91d0, republished under its MIT licence (© AgentSystemLabs). 500 words, ~1,461 tokens.

name

diagram

description

Show Mermaid diagrams in Mission Control's diagram viewer instead of dumping raw syntax in the terminal. Use when the user asks for a diagram, flowchart, sequence diagram, architecture sketch, state machine, ER diagram, or any visual that Mermaid can render — and whenever a diagram would clarify a complex flow. Requires a Mission Control agent session (MC_API_URL and MC_API_TOKEN are injected automatically). Not for ASCII art in chat, image generation, or projects running outside Mission Control.

user-invocable

true

POST $MC_API_URL/api/diagram?taskId=$MC_TASK_ID
Authorization: Bearer $MC_API_TOKEN
Content-Type: application/json

{
  "source": "<mermaid source>",
  "title": "Optional title shown in the modal",
  "format": "mermaid",
  "theme": "dark"
}

sequenceDiagram
  participant U as User
  participant MC as Mission Control
  U->>MC: POST /api/diagram
  MC-->>U: Open themed viewer

curl -sS -X POST "$MC_API_URL/api/diagram?taskId=$MC_TASK_ID" \
  -H "Authorization: Bearer $MC_API_TOKEN" \
  -H "Content-Type: application/json" \
  -d @- <<EOF
{
  "source": "flowchart LR\n  A[Draft Mermaid] --> B[POST /api/diagram]\n  B --> C[Modal opens]",
  "title": "Diagram pipeline",
  "format": "mermaid",
  "theme": "${MC_THEME:-dark}"
}
EOF

curl -sS -X POST "$MC_API_URL/api/diagram?taskId=$MC_TASK_ID" \
  -H "Authorization: Bearer $MC_API_TOKEN" \
  -H "Content-Type: application/json" \
  -d "$(jq -n \
    --arg source 'sequenceDiagram
  participant U as User
  participant MC as Mission Control
  participant A as Agent CLI
  U->>MC: Start session
  MC->>A: Spawn PTY + env
  A->>MC: POST /api/diagram
  MC-->>U: Open diagram modal' \
    --arg title 'Session diagram flow' \
    --arg theme "${MC_THEME:-dark}" \
    '{source:$source,title:$title,format:"mermaid",theme:$theme}')"

curl -sS -X POST "$MC_API_URL/api/diagram?taskId=$MC_TASK_ID" \
  -H "Authorization: Bearer $MC_API_TOKEN" \
  -H "Content-Type: application/json" \
  -d "$(jq -n \
    --arg source 'flowchart LR
  A[Draft Mermaid] --> B[POST /api/diagram]
  B --> C[Modal opens]' \
    --arg title 'Diagram pipeline' \
    --arg theme "${MC_THEME:-dark}" \
    '{source:$source,title:$title,format:"mermaid",theme:$theme}')"

© AgentSystemLabs, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

Just SKILL.md in .agents/skills/diagram of AgentSystemLabs/mission-control.

Open the folder on GitHubat commit 92b91d0

Used in 2 other repositories

We found 6 copies of this SKILL.md (exact, near-identical or edited) in other folders, from 1 other GitHub owner. This page covers the copy in AgentSystemLabs/mission-control, which our catalogue first saw on October 7, 2026.

• AgentSystemLabs/core.agents/skills/diagram.claude/skills/diagram
• webdevcody/sketchlab.app.codex/skills/diagram.agents/skills/diagram+2 more