spec-pane by pierrebelin: Claude Code mod code

What it does

Draws a pane
Adds /spec-pane
Watches tool calls and can refuse them
Hooks prompt.submit, session.start

Good points

No network calls
Starts no processes
Written in TypeScript
Handles errors

Code to start from

A starter ModsCode writes from the drawing it read, and the mod's own lines that draw, where there are any.

Starter (register.tsx)

import type { Register } from 'claude-code'

// Drawn like spec-pane by Pierre Belin (pane), as ModsCode read it from the mod's code:
// https://modscode.com/claude-mods/mods/pierrebelin-spec-pane/
// Written by ModsCode from that reading, not copied from the mod: use it as you like.
// Each value below stands for one the mod works out at run time; put in your own.
export const register: Register = on => {
  // the pane: open it with $.ui.open({ id: 'my-pane', title: "Spec" })
  on('ui.render', { component: 'Pane', requestId: 'my-pane' }, async ($, e) => {
    const { Box, Text, Button } = $.ui.resolve(e)
    const title = '…'
    const location = '…'
    const freshness = '…'
    const length = '…'
    const summary = '…'
    const pending = '…'
    const id = '…'
    const name = '…'
    const severity = '…'
    const id2 = '…'
    const name2 = '…'
    const severity2 = '…'
    const id3 = '…'
    const name3 = '…'
    const severity3 = '…'
    const id4 = '…'
    const name4 = '…'
    const severity4 = '…'
    const id5 = '…'
    const name5 = '…'
    const severity5 = '…'
    const id6 = '…'
    const name6 = '…'
    const severity6 = '…'
    return (
      <Box flexDirection="column" marginTop={1}>
        <Box height={1}>
          <Box flexGrow={1} flexShrink={1}>
            <Text wrap="truncate-end">
              <Text color="claude">
                {"✻ "}
              </Text>
              <Text color="inactive">
                Spec
                {" › "}
              </Text>
              <Text bold>
                {title}
              </Text>
            </Text>
          </Box>
          <Button label="✕" plain dimColor />
        </Box>
        <Text color="inactive" wrap="truncate-start">
          {"  ⎿  "}
          {location}
          {freshness}
        </Text>
        <Box height={1}>
          <Text>
            {"     "}
          </Text>
          <Button hotkey="b" plain dimColor>
            <Text>
              {`fold all (${length} open)`}
            </Text>
          </Button>
        </Box>
        <Box marginTop={1}>
          <Text color="inactive" wrap="wrap">
            {summary}
          </Text>
        </Box>
        <Box flexDirection="column" marginTop={1}>
          <Box height={1}>
            <Button plain dimColor>
              ▾
            </Button>
            <Text bold>
              {" "}
              Decisions
            </Text>
            <Text color="inactive">
              {" "}
              {`${length} · ${pending} pending`}
            </Text>
          </Box>
        </Box>
        <Box flexDirection="column" marginTop={1}>
          <Box height={1}>
            <Button plain dimColor>
              ▾
            </Button>
            <Text bold>
              {" "}
              Open questions
            </Text>
            <Text color="inactive">
              {" "}
              none
            </Text>
          </Box>
        </Box>
        <Box flexDirection="column" marginTop={1}>
          <Box height={1}>
            <Button plain dimColor>
              ▾
            </Button>
            <Text bold>
              {" "}
              Use cases
            </Text>
            <Text color="inactive">
              {" "}
              {`${length}`}
            </Text>
          </Box>
          <Box height={1}>
            <Text color="inactive">
              {"▾ "}
            </Text>
            <Button plain>
              <Text color="inactive">
                {id}
                {" "}
              </Text>
              <Text wrap="truncate-end">
                {name}
              </Text>
            </Button>
          </Box>
          <Box flexDirection="column" marginLeft={4} marginBottom={1}>
            <Text>
              {severity}
            </Text>
            <Box marginTop={1}>
              <Text bold>
                Impact
              </Text>
            </Box>
            <Text wrap="wrap">
              {" "}
            </Text>
            <Text wrap="wrap">
              {" "}
            </Text>
            <Text wrap="wrap">
              {" "}
            </Text>
            <Box marginTop={1}>
              <Text bold>
                Options
              </Text>
            </Box>
            <Text wrap="wrap">
              {" "}
            </Text>
            <Text wrap="wrap">
              {" "}
            </Text>
            <Text wrap="wrap">
              {" "}
            </Text>
          </Box>
          <Box height={1}>
            <Text color="inactive">
              {"▾ "}
            </Text>
            <Button plain>
              <Text color="inactive">
                {id2}
                {" "}
              </Text>
              <Text wrap="truncate-end">
                {name2}
              </Text>
            </Button>
          </Box>
          <Box flexDirection="column" marginLeft={4} marginBottom={1}>
            <Text>
              {severity2}
            </Text>
            <Box marginTop={1}>
              <Text bold>
                Impact
              </Text>
            </Box>
            <Text wrap="wrap">
              {" "}
            </Text>
            <Text wrap="wrap">
              {" "}
            </Text>
            <Text wrap="wrap">
              {" "}
            </Text>
            <Box marginTop={1}>
              <Text bold>
                Options
              </Text>
            </Box>
            <Text wrap="wrap">
              {" "}
            </Text>
            <Text wrap="wrap">
              {" "}
            </Text>
            <Text wrap="wrap">
              {" "}
            </Text>
          </Box>
          <Box height={1}>
            <Text color="inactive">
              {"▾ "}
            </Text>
            <Button plain>
              <Text color="inactive">
                {id3}
                {" "}
              </Text>
              <Text wrap="truncate-end">
                {name3}
              </Text>
            </Button>
          </Box>
          <Box flexDirection="column" marginLeft={4} marginBottom={1}>
            <Text>
              {severity3}
            </Text>
            <Box marginTop={1}>
              <Text bold>
                Impact
              </Text>
            </Box>
            <Text wrap="wrap">
              {" "}
            </Text>
            <Text wrap="wrap">
              {" "}
            </Text>
            <Text wrap="wrap">
              {" "}
            </Text>
            <Box marginTop={1}>
              <Text bold>
                Options
              </Text>
            </Box>
            <Text wrap="wrap">
              {" "}
            </Text>
            <Text wrap="wrap">
              {" "}
            </Text>
            <Text wrap="wrap">
              {" "}
            </Text>
          </Box>
        </Box>
        <Box flexDirection="column" marginTop={1}>
          <Box height={1}>
            <Button plain dimColor>
              ▾
            </Button>
            <Text bold>
              {" "}
              Business rules
            </Text>
            <Text color="inactive">
              {" "}
              {`${length}`}
            </Text>
          </Box>
          <Box height={1}>
            <Text color="inactive">
              {"▾ "}
            </Text>
            <Button plain>
              <Text color="inactive">
                {id4}
                {" "}
              </Text>
              <Text wrap="truncate-end">
                {name4}
              </Text>
            </Button>
          </Box>
          <Box flexDirection="column" marginLeft={4} marginBottom={1}>
            <Text>
              {severity4}
            </Text>
            <Box marginTop={1}>
              <Text bold>
                Impact
              </Text>
            </Box>
            <Text wrap="wrap">
              {" "}
            </Text>
            <Text wrap="wrap">
              {" "}
            </Text>
            <Text wrap="wrap">
              {" "}
            </Text>
            <Box marginTop={1}>
              <Text bold>
                Options
              </Text>
            </Box>
            <Text wrap="wrap">
              {" "}
            </Text>
            <Text wrap="wrap">
              {" "}
            </Text>
            <Text wrap="wrap">
              {" "}
            </Text>
          </Box>
          <Box height={1}>
            <Text color="inactive">
              {"▾ "}
            </Text>
            <Button plain>
              <Text color="inactive">
                {id5}
                {" "}
              </Text>
              <Text wrap="truncate-end">
                {name5}
              </Text>
            </Button>
          </Box>
          <Box flexDirection="column" marginLeft={4} marginBottom={1}>
            <Text>
              {severity5}
            </Text>
            <Box marginTop={1}>
              <Text bold>
                Impact
              </Text>
            </Box>
            <Text wrap="wrap">
              {" "}
            </Text>
            <Text wrap="wrap">
              {" "}
            </Text>
            <Text wrap="wrap">
              {" "}
            </Text>
            <Box marginTop={1}>
              <Text bold>
                Options
              </Text>
            </Box>
            <Text wrap="wrap">
              {" "}
            </Text>
            <Text wrap="wrap">
              {" "}
            </Text>
            <Text wrap="wrap">
              {" "}
            </Text>
          </Box>
          <Box height={1}>
            <Text color="inactive">
              {"▾ "}
            </Text>
            <Button plain>
              <Text color="inactive">
                {id6}
                {" "}
              </Text>
              <Text wrap="truncate-end">
                {name6}
              </Text>
            </Button>
          </Box>
          <Box flexDirection="column" marginLeft={4} marginBottom={1}>
            <Text>
              {severity6}
            </Text>
            <Box marginTop={1}>
              <Text bold>
                Impact
              </Text>
            </Box>
            <Text wrap="wrap">
              {" "}
            </Text>
            <Text wrap="wrap">
              {" "}
            </Text>
            <Text wrap="wrap">
              {" "}
            </Text>
            <Box marginTop={1}>
              <Text bold>
                Options
              </Text>
            </Box>
            <Text wrap="wrap">
              {" "}
            </Text>
            <Text wrap="wrap">
              {" "}
            </Text>
            <Text wrap="wrap">
              {" "}
            </Text>
          </Box>
        </Box>
        <Box flexDirection="column" marginTop={1}>
          <Box height={1}>
            <Button plain dimColor>
              ▾
            </Button>
            <Text bold>
              {" "}
              Sections
            </Text>
            <Text color="inactive">
              {" "}
              {`${length}`}
            </Text>
          </Box>
        </Box>
      </Box>
    )
  })
}

The mod's own code

Shown under the mod's licence (MIT); its text is below. Keep the notice if you copy these lines.

mods/spec-pane/hooks/register.tsx lines 319–478 · Pane

mods/spec-pane/hooks/register.tsx:319

  on('ui.render', { component: 'Pane', requestId: PANE }, async ($, e) => {
    const { Box, Button, Text } = $.ui.resolve(e)
    const state = await read($, tracked)
    const asked = await read($, decisions)
    const where: Navigation = { ...HOME, ...(await read($, nav)) }
    const at = await read($, now)
    const doc = state.doc
    const columns = e.props.bodyColumns
    const slot = (kind: Kind, id: string) => `${kind}:${id}`
    const isExpanded = (kind: Kind, id: string) => where.expanded.includes(slot(kind, id))
    const expand = (kind: Kind, id: string) => () =>
      void update($, nav, current => {
        const expanded = current.expanded ?? []
        const one = slot(kind, id)
        return { ...HOME, ...current, expanded: expanded.includes(one) ? expanded.filter(other => other !== one) : [...expanded, one] }
      })
    const foldAll = () => void update($, nav, current => ({ ...HOME, ...current, expanded: [] }))
    const toggle = (group: string) => () =>
      void update($, nav, current => ({
        ...current,
        collapsed: current.collapsed.includes(group) ? current.collapsed.filter(one => one !== group) : [...current.collapsed, group],
      }))
    const isOpen = (group: string) => !where.collapsed.includes(group)

    const close = <Button key="close" label="✕" plain dimColor onPress={() => $.ui.close({ id: PANE })} />
    const header = (title: string, trail?: string) => (
      <Box key="header" height={1}>
        <Box flexGrow={1} flexShrink={1}>
          <Text wrap="truncate-end">
            <Text color="claude">✻ </Text>
            {trail !== undefined && <Text color="inactive">{trail} › </Text>}
            <Text bold>{title}</Text>
          </Text>
        </Box>
        {close}
      </Box>
    )
    const paragraph = (key: string, text: string, color?: string) =>
      text
        .split('\n')
        .filter((line, index, all) => line.trim() !== '' || (index > 0 && all[index - 1]?.trim() !== ''))
        .map((line, index) => (
          <Text key={`${key}-${index}`} color={color} wrap="wrap">
            {plain(line) || ' '}
          </Text>
        ))

    const detail = (kind: Kind, id: string): JSX.Element[] | null => {
      if (kind === 'decision') {
        const decision = asked.find(one => one.id === id)
        if (decision === undefined) return null
        return [
          <Text key="d-question" bold wrap="wrap">
            {decision.question}
          </Text>,
          ...decision.options.map((option, index) => {
            const isChosen = decision.answer?.split(', ').includes(option) ?? false
            return (
              <Text key={`d-option-${index}`} wrap="wrap" color={isChosen ? 'success' : 'inactive'}>
                {isChosen ? '  ✓ ' : '    '}
                {option}
                {option === decision.recommended ? ' ★' : ''}
              </Text>
            )
          }),
          <Box key="d-answer" marginTop={1}>
            <Text wrap="wrap" color={decision.isPending ? 'claude' : isOffRecommendation(decision) ? 'warning' : undefined}>
              {decision.isPending ? 'Waiting for the answer…' : `Answer: ${decision.answer ?? '—'}`}
            </Text>
          </Box>,
          ...(decision.note === null ? [] : [<Text key="d-note" color="inactive" wrap="wrap">{`Note: ${decision.note}`}</Text>]),
        ]
      }
      if (doc === null) return null
      if (kind === 'openQuestion') {
        const question = doc.openQuestions.find(one => one.id === id)
        if (question === undefined) return null
        return [
          <Text key="q-severity" color={severityTone(question.severity)}>
            {question.severity}
          </Text>,
          <Box key="q-impact-title" marginTop={1}>
            <Text bold>Impact</Text>
          </Box>,
          ...paragraph('q-impact', question.impact),
          <Box key="q-options-title" marginTop={1}>
            <Text bold>Options</Text>
          </Box>,
          ...paragraph('q-options', question.options),
        ]
      }
      if (kind === 'section') {
        const section = doc.sections.find(one => one.number === id)
        return section === undefined ? null : paragraph('s', section.body)
      }
      const item = (kind === 'useCase' ? doc.useCases : doc.rules).find(one => one.id === id)
      return item === undefined ? null : paragraph('i', item.body)
    }

    if (!state.isArmed && doc === null) {
      return (
        <Box flexDirection="column" marginTop={1}>
          {header(TITLE)}
          <Text color="inactive" wrap="truncate-end">
            {'  ⎿  '}No /business-spec in this session yet.
          </Text>
        </Box>
      )
    }

    const group = (key: (typeof GROUPS)[number], title: string, count: string, rows: JSX.Element[], tone?: string) => (
      <Box key={`group-${key}`} flexDirection="column" marginTop={1}>
        <Box height={1}>
          <Button key={`toggle-${key}`} plain dimColor onPress={toggle(key)}>
            {isOpen(key) ? '▾' : '▸'}
          </Button>
          <Text bold> {title}</Text>
          <Text color={tone ?? 'inactive'}> {count}</Text>
        </Box>
        {isOpen(key) && rows}
      </Box>
    )
    const unfolded = (kind: Kind, id: string): JSX.Element[] => {
      if (!isExpanded(kind, id)) return []
      const body = detail(kind, id)
      return body === null
        ? []
        : [
            <Box key={`detail-${kind}-${id}`} flexDirection="column" marginLeft={4} marginBottom={1}>
              {body}
            </Box>,
          ]
    }
    const entry = (kind: Kind, id: string, children: JSX.Element[]) => [
      <Box key={`row-${kind}-${id}`} height={1}>
        <Text color="inactive">{isExpanded(kind, id) ? '▾ ' : '  '}</Text>
        <Button key={`open-${kind}-${id}`} plain onPress={expand(kind, id)}>
          {children}
        </Button>
      </Box>,
      ...unfolded(kind, id),
    ]

    const pending = asked.filter(one => one.isPending).length
    const decisionRows = asked.flatMap(decision =>
      entry('decision', decision.id, [
        <Text key="mark" color={decision.isPending ? 'claude' : isOffRecommendation(decision) ? 'warning' : 'success'}>
          {decision.isPending ? '? ' : isOffRecommendation(decision) ? '≠ ' : '✓ '}
        </Text>,
        <Text key="text" wrap="truncate-end">
          {fit(
            `${decision.header !== '' ? `${decision.header} · ` : ''}${decision.isPending ? decision.question : (decision.answer ?? '—')}`,
            columns - 4,
          )}
        </Text>,
      ]),
    )

    const openQuestions = doc?.openQuestions ?? []
    const blocking = blockingCount(openQuestions)

Licence text (MIT)

MIT License

Copyright (c) 2026 Pierre Belin

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

How to build this: Pane (panel), Deny a tool call

What its code calls

reads filestool calls

What its code shows

Read from the source at commit 85b88e6fe092 on 2026-10-11. The first group decides whether a mod is listed; the rest is for you to weigh. A later commit is not read until the next crawl.

Decides the listing: code you can check
Entry read	Every module hooks/hooks.json names was read.mods/spec-pane/hooks/register.tsx
Parses	Every file parses as TypeScript or JavaScript.1 files parsed
All its code is in the mod	Every import is a file of the mod or the engine's own module; no packages, no require.all its code is in the mod
Readable	No minified lines, no eval or new Function, no import of a computed path, no encoded blobs.no minified code, no eval, no encoded blobs
Calls in the open	Network and programs are reached as $.http.fetch and $.process.run in place, never passed around.every call outside goes through $ in the open
For you to weigh before installing
Where it draws	The terminal, the desktop app, both, or nothing (hooks only: a guard or a prompt rewriter), as its code says. Shown, never a reason to leave a mod out.draws in the terminal and the desktop app, the same in both
Install line	Whether its repository's own .claude-plugin/marketplace.json lists it, so it installs from that marketplace with the lines on its page.listed in its repository's .claude-plugin/marketplace.json: installs from there
Programs on Windows	Whether every program it starts through $.process exists on Windows (tail, date, open, osascript, /usr/… do not).runs no program a Windows PC lacks
Network	Whether every fetch names its https host in the code.no network
Programs	Whether every program it starts is named in the code and is not a shell, an interpreter or a network tool.starts no programs
Reads and sends	Whether it both reads something of yours (files, environment variables, the transcript, settings) and reaches outside (the network, an MCP server, another session, telemetry).reads files, but reaches nothing outside
Keys in the source	Whether the source holds what looks like an API key or a private key.no keys in the source
Licence	An open licence (MIT, Apache-2.0, BSD, ISC, Unlicense, 0BSD, CC0) with its text lets ModsCode show its code; otherwise the code is linked.MIT
Settings hooks	Hooks declared in hooks/hooks.json or plugin.json beside the module: a command (a shell when it has no args), an HTTP request, an MCP tool or a model prompt at an event. They run outside $.no settings hooks: its function hooks alone
Servers it ships	MCP servers (a program, or a URL; a headersHelper is a shell command; a .mcpb bundle is unpacked at run time), LSP servers, monitors (a shell command for the whole session) and bin/ (on the PATH of the Bash tool).ships no MCP or LSP server, no monitor, no bin/
Skills, commands, agents	What its Markdown declares beyond text: allowed-tools granted for the turn, hooks added when a skill is invoked, a command run before Claude reads the skill.no skills, commands, agents or workflows
Tools and MCP	Whether every tool it calls through $.tool.call and $.mcp.call is named in the code, and none is a shell (Bash through the tool runs a shell without $.process).calls no tool, MCP server or command
Asks of the model	Completions it runs ($.model.complete, fork, classify), subagents it spawns, prompts it submits as you, and the tools, commands and agents it adds.adds command spec-pane
Events it hooks	By what a hook there can do: gates (refuse a tool call, a prompt, a setting, another plugin), shapes (what the model reads: the system prompt, tool descriptions, each request), reads (your input, the events of the settings hooks, every event with *), and the rest.gates: command.run (spec-pane), prompt.submit, tool.call · also: session.start, ui.render (Pane) · timers: clock.every
Reads, by name	The environment variables and files it names, and whether it reads the transcript, settings.json, the prompt box or the mouse selection.files: a path computed at run time
Writes, by name	The files and environment variables it names, and whether it changes settings, the prompt box, the clipboard, the conversation (a row the model reads) or another session.writes no files, environment variables, settings or conversation rows

This is a reading of the code text, not a security review: it does not run the mod, and it cannot see what a program the mod starts does. The check before installing is yours. How mods are chosen

Install it

Check it yourself before you install it. Mods run unsandboxed, with your permissions, and ModsCode does not vouch for what this code does. Read its code (or run claude plugin validate . in its folder), weigh what it reaches, and install the commit you read.

From its marketplace

Its repository is its marketplace. Add that marketplace (in the terminal with these commands, or in the desktop app's plugin settings) and install the mod from it:

/plugin marketplace add pierrebelin/claude-code-toolkit

/plugin install spec-pane@cctoolkit

/reload-plugins

This installs the marketplace's latest commit, which may not be the one read here (85b88e6fe092). Compare them before you install. /reload-plugins loads it into a session that is already open.

Try the commit ModsCode read

No marketplace needed. In a terminal, clone the repository, check out the commit read, validate the mod, and load it for one session:

git clone https://github.com/pierrebelin/claude-code-toolkit

git -C claude-code-toolkit checkout 85b88e6fe09261b4b8101440b1e232f3ea8dbf74

claude plugin validate claude-code-toolkit/mods/spec-pane

claude --plugin-dir claude-code-toolkit/mods/spec-pane

The validate line lists the events the mod hooks and what it asks Claude Code to do, without running it. The last line loads the mod for this session only and writes nothing to your settings. If the author has rewritten history, the commit may no longer exist.

Ask Claude about it

With the ModsCode connector added, Claude can read this mod's code and what it reaches, and build on them. Ask it like this:

Read the ModsCode mod "pierrebelin-spec-pane" with its code and make me one like it

Search them from Claude: the MCP connector

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Badge for your README

If this is your mod, paste this into your README. It links to this page.

README.md

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