Plans palette, type, and layout for a specific brief, then builds the UI.

How it works

Foe: Blank Mimic, an empty screen or canvas that needs a design.

Foes

  • Blank Mimic

Party · Context

  • IllusionistYour agent100/100
  1. Blank Mimic

    The Blank Mimic blocks the way.

    What really happensIt stands for an empty screen or canvas that needs a design.

    Illusionist: Context 100/100.

  2. Blank stare

    The blank page stares back and drains the hero.

    What really happensStarting a screen from nothing costs time and context.

    Illusionist takes 9. Illusionist: Context 91/100.

  3. Anthropic Frontend Design

    The hero unrolls the Frontend Design scroll before drawing a screen.

    What really happensThe agent loads the frontend-design skill when you ask for new UI or a reshape of an existing one.

    Blank Mimic takes 19.

  4. Anthropic Frontend Design

    It names colors, type, and layout for this subject before any code.

    What really happensIt writes a short plan: 4 to 6 named hex colors, typefaces and roles, a layout with an ASCII wireframe, and what should make this page specific.

    Blank Mimic takes 16.

  5. Blank stare

    The Blank Mimic uses Blank stare.

    Illusionist takes 9. Illusionist: Context 82/100.

  6. Anthropic Frontend Design

    Hammer sparks as the page is built from the revised plan.

    What really happensAfter checking the plan against the brief, it writes the interface, including copy when the brief has none.

    Blank Mimic takes 24.

  7. Anthropic Frontend Design

    A ward checks focus, motion, and whether one bold choice is enough.

    What really happensIt aims for a mobile layout, visible keyboard focus, reduced motion, and accessible color, and cuts decoration that does not serve the brief.

    Blank Mimic takes 10. Illusionist: Ward.

  8. Anthropic Frontend Design

    The Blank Mimic takes a shape that belongs to this subject.

    What really happensYou get interface code whose palette, type, and layout were chosen for this brief, with one memorable element and the rest kept quiet.

    Blank Mimic takes 31. Blank Mimic falls.

  9. Victory

    The Blank Mimic falls.

Learn this spell

Claude Code

/plugin marketplace add anthropics/skills
/plugin install example-skills@anthropic-agent-skills

Notes

Claude Code install is the example-skills plugin from anthropics/skills; no Codex install is documented. The SKILL.md also works on its own. It does not open a browser or a design file. The agent plans tokens, checks them against the brief, then writes code. Screenshots are used only if the environment can take them. Skip this if you already installed the official frontend-design plugin, which ships the same skill.

Proving Grounds record

Controlled quest results, separate from recorded usage. Each setup pools runs across its quests. The per-quest table below has casts, cast time, mana, incantation and runes; medians are not pooled.

Hero: Claude Code 2.1.305; weapon (model): claude-haiku-5-5; charge (effort): low; arena: sealed; invoked cast (the prompt named the skill). macOS 27.0.1, arm64. Curator.

Clear rate50%3 of 6 runs passed every check; Unarmed: 2 of 6 (matched quests)
Steadiness19%reliability: Wilson 95% lower bound
Buff+17 ppvs Unarmed, only matched quests (6 equipped runs; 6 control runs)
Instant casts0 of 6runs cleared on the first prompt; Unarmed: 0 of 6 (matched quests)
Attunement83%5 of 6 runs opened an equipped skill
Upkeep-24% manaextra mana per run vs Unarmed, median of 2 quests
IncantationNot measuredoutput tokens per run vs Unarmed
Runes+1%lines added per run vs Unarmed, median of 2 quests

Hero: Claude Code 2.1.305; weapon (model): claude-opus-5-5; charge (effort): high; arena: sealed; invoked cast (the prompt named the skill). macOS 27.0.1, arm64. Curator.

Clear rate44%4 of 9 runs passed every check; Unarmed: 3 of 9 (matched quests)
Steadiness19%reliability: Wilson 95% lower bound
Buff+11 ppvs Unarmed, only matched quests (9 equipped runs; 9 control runs)
Instant casts4 of 9runs cleared on the first prompt; Unarmed: 3 of 9 (matched quests)
Attunement100%9 of 9 runs opened an equipped skill
Upkeep+2% manaextra mana per run vs Unarmed, median of 2 quests
IncantationNot measuredoutput tokens per run vs Unarmed
Runes-4%lines added per run vs Unarmed, median of 2 quests

Hero: Claude Code 2.1.305; weapon (model): claude-sonnet-5-5; charge (effort): medium; arena: sealed; invoked cast (the prompt named the skill). macOS 27.0.1, arm64. Curator.

Clear rate50%4 of 8 runs passed every check; Unarmed: 22 of 32 (matched quests)
Steadiness22%reliability: Wilson 95% lower bound
Buff-19 pp debuffvs Unarmed, only matched quests (8 equipped runs; 32 control runs)
Instant casts1 of 8runs cleared on the first prompt; Unarmed: 9 of 32 (matched quests)
Attunement100%8 of 8 runs opened an equipped skill
Upkeep+28% manaextra mana per run vs Unarmed, median of 2 quests
IncantationNot measuredoutput tokens per run vs Unarmed
Runes+4%lines added per run vs Unarmed, median of 2 quests

Hero: OMP 18.8.3; weapon (model): anthropic/claude-sonnet-5-5; charge (effort): medium; arena: warded; invoked cast (the prompt named the skill). macOS 27.0.1, arm64. Curator.

Clear rate0%0 of 3 runs passed every check; Unarmed: 1 of 6 (matched quests)
Steadiness0%reliability: Wilson 95% lower bound
Buff-17 pp debuffvs Unarmed, only matched quests (3 equipped runs; 6 control runs)
Instant casts0 of 3runs cleared on the first prompt; Unarmed: 1 of 6 (matched quests)
Attunement100%3 of 3 runs opened an equipped skill
Upkeep+38% manaextra mana per run vs Unarmed, median of 1 quest
IncantationNot measuredoutput tokens per run vs Unarmed
Runes+13%lines added per run vs Unarmed, median of 1 quest

Hero: Claude Code 2.1.305; weapon (model): claude-sonnet-5-5; charge (effort): medium; arena: sealed; ambient cast (the agent chose). macOS 27.0.1, arm64. Curator.

Clear rate75%3 of 4 runs passed every check; Unarmed: 22 of 32 (matched quests)
Steadiness30%reliability: Wilson 95% lower bound
Buff+6 ppvs Unarmed, only matched quests (4 equipped runs; 32 control runs)
Instant casts1 of 4runs cleared on the first prompt; Unarmed: 9 of 32 (matched quests)
Attunement0%0 of 4 runs opened an equipped skill
Upkeep+19% manaextra mana per run vs Unarmed, median of 2 quests
IncantationNot measuredoutput tokens per run vs Unarmed
Runes+8%lines added per run vs Unarmed, median of 2 quests
Per-quest Proving Grounds record
QuestFixed taskClear ratePassed runsSteadinessReliability lower boundBuffClear-rate points vs UnarmedInstant castsFirst-prompt clearsCastsPrompts to clearCast timeAgent runtimeManaCost at API list pricesIncantationOutput tokensRunesLines added / removedAttunementSkills openedSetupApp, model, effort and sandbox
Illusionist: pricing plan switcherQuest v80%0 of 3Unarmed: 0% (0 of 3)0%+0 ppvs Unarmed0 of 30%Unarmed: 0 of 3Not reported1m 36sUnarmed: 2m 24s188 Unarmed: 278Not reportedUnarmed: Not reported+480 / -3Unarmed: +508 / -3100%Hero: Claude Code 2.1.305; weapon (model): claude-haiku-5-5; charge (effort): low; arena: sealed; invoked cast (the prompt named the skill).
macOS 27.0.1, arm64. Curator.
0 mishaps excluded. 2026-10-21 to 2026-10-21.Scrying (screenshot)
Try this loadout
node "<spell-report-skill-directory>/scripts/spell-report.mjs" trial --spell anthropic-frontend-design --quest illusionist-pricing-tabs --hero claude-code --weapon 'claude-haiku-5-5' --charge low --cast invoked --control

Recorded with quest v8 and spell commits anthropic-frontend-design@dbd4588f9e1033efb41dad4bef2f7947c8993d44. How to run it

Illusionist: pricing plan switcherQuest v817%1 of 6Unarmed: 33% (2 of 6)3%-17 pp debuffvs Unarmed1 of 617%Unarmed: 2 of 615m 54sUnarmed: 4m 38s12,637 Unarmed: 9,828Not reportedUnarmed: Not reported+699 / -2Unarmed: +730 / -2100%Hero: Claude Code 2.1.305; weapon (model): claude-opus-5-5; charge (effort): high; arena: sealed; invoked cast (the prompt named the skill).
macOS 27.0.1, arm64. Curator.
0 mishaps excluded. 2026-10-21 to 2026-10-21.Scrying (screenshot)
Try this loadout
node "<spell-report-skill-directory>/scripts/spell-report.mjs" trial --spell anthropic-frontend-design --quest illusionist-pricing-tabs --hero claude-code --weapon 'claude-opus-5-5' --charge high --cast invoked --control

Recorded with quest v8 and spell commits anthropic-frontend-design@dbd4588f9e1033efb41dad4bef2f7947c8993d44. How to run it

Illusionist: pricing plan switcherQuest v820%1 of 5Unarmed: 53% (9 of 17)4%-33 pp debuffvs Unarmed1 of 520%Unarmed: 9 of 1711m 37sUnarmed: 1m 37s2,823 Unarmed: 2,764Not reportedUnarmed: 14.5k+380 / -3Unarmed: +394 / -3100%Hero: Claude Code 2.1.305; weapon (model): claude-sonnet-5-5; charge (effort): medium; arena: sealed; invoked cast (the prompt named the skill).
macOS 27.0.1, arm64. Curator.
0 mishaps excluded. 2026-10-21 to 2026-10-21.Scrying (screenshot)
Try this loadout
node "<spell-report-skill-directory>/scripts/spell-report.mjs" trial --spell anthropic-frontend-design --quest illusionist-pricing-tabs --hero claude-code --weapon 'claude-sonnet-5-5' --charge medium --cast invoked --control

Recorded with quest v8 and spell commits anthropic-frontend-design@dbd4588f9e1033efb41dad4bef2f7947c8993d44. How to run it

Illusionist: pricing plan switcherQuest v850%1 of 2Unarmed: 53% (9 of 17)9%-3 pp debuffvs Unarmed1 of 250%Unarmed: 9 of 1711m 55sUnarmed: 1m 37s3,006 Unarmed: 2,764Not reportedUnarmed: 14.5k+406 / -3Unarmed: +394 / -30%Hero: Claude Code 2.1.305; weapon (model): claude-sonnet-5-5; charge (effort): medium; arena: sealed; ambient cast (the agent chose).
macOS 27.0.1, arm64. Curator.
0 mishaps excluded. 2026-10-21 to 2026-10-21.Scrying (screenshot)
Try this loadout
node "<spell-report-skill-directory>/scripts/spell-report.mjs" trial --spell anthropic-frontend-design --quest illusionist-pricing-tabs --hero claude-code --weapon 'claude-sonnet-5-5' --charge medium --cast ambient --control

Recorded with quest v8 and spell commits anthropic-frontend-design@dbd4588f9e1033efb41dad4bef2f7947c8993d44. How to run it

Illusionist: pricing plan switcherQuest v80%0 of 3Unarmed: 17% (1 of 6)0%-17 pp debuffvs Unarmed0 of 30%Unarmed: 1 of 6Not reported1m 19sUnarmed: 1m 6s2,131 Unarmed: 1,541Not reportedUnarmed: 10.2k+415 / -3Unarmed: +368 / -3100%Hero: OMP 18.8.3; weapon (model): anthropic/claude-sonnet-5-5; charge (effort): medium; arena: warded; invoked cast (the prompt named the skill).
macOS 27.0.1, arm64. Curator.
0 mishaps excluded. 2026-10-21 to 2026-10-21.Scrying (screenshot)
Try this loadout
node "<spell-report-skill-directory>/scripts/spell-report.mjs" trial --spell anthropic-frontend-design --quest illusionist-pricing-tabs --hero omp --weapon 'anthropic/claude-sonnet-5-5' --charge medium --cast invoked --control

Recorded with quest v8 and spell commits anthropic-frontend-design@dbd4588f9e1033efb41dad4bef2f7947c8993d44. How to run it

Illusionist: booking form repairQuest v4100%3 of 3Unarmed: 67% (2 of 3)44%+33 ppvs Unarmed0 of 30%Unarmed: 0 of 321m 47sUnarmed: 2m 10s230 Unarmed: 271Not reportedUnarmed: Not reported+170 / -81Unarmed: +158 / -7967%Hero: Claude Code 2.1.305; weapon (model): claude-haiku-5-5; charge (effort): low; arena: sealed; invoked cast (the prompt named the skill).
macOS 27.0.1, arm64. Curator.
0 mishaps excluded. 2026-10-21 to 2026-10-21.Scrying (screenshot)
Try this loadout
node "<spell-report-skill-directory>/scripts/spell-report.mjs" trial --spell anthropic-frontend-design --quest illusionist-signup-form --hero claude-code --weapon 'claude-haiku-5-5' --charge low --cast invoked --control

Recorded with quest v4 and spell commits anthropic-frontend-design@dbd4588f9e1033efb41dad4bef2f7947c8993d44. How to run it

Illusionist: booking form repairQuest v4100%3 of 3Unarmed: 33% (1 of 3)44%+67 ppvs Unarmed3 of 3100%Unarmed: 1 of 312m 46sUnarmed: 3m 44s6,533 Unarmed: 8,662Not reportedUnarmed: Not reported+236 / -85Unarmed: +245 / -86100%Hero: Claude Code 2.1.305; weapon (model): claude-opus-5-5; charge (effort): high; arena: sealed; invoked cast (the prompt named the skill).
macOS 27.0.1, arm64. Curator.
0 mishaps excluded. 2026-10-21 to 2026-10-21.Scrying (screenshot)
Try this loadout
node "<spell-report-skill-directory>/scripts/spell-report.mjs" trial --spell anthropic-frontend-design --quest illusionist-signup-form --hero claude-code --weapon 'claude-opus-5-5' --charge high --cast invoked --control

Recorded with quest v4 and spell commits anthropic-frontend-design@dbd4588f9e1033efb41dad4bef2f7947c8993d44. How to run it

Illusionist: booking form repairQuest v4100%3 of 3Unarmed: 87% (13 of 15)44%+13 ppvs Unarmed0 of 30%Unarmed: 0 of 1521m 23sUnarmed: 1m 6s2,724 Unarmed: 1,761Not reportedUnarmed: 12.2k+127 / -69Unarmed: +114 / -61100%Hero: Claude Code 2.1.305; weapon (model): claude-sonnet-5-5; charge (effort): medium; arena: sealed; invoked cast (the prompt named the skill).
macOS 27.0.1, arm64. Curator.
0 mishaps excluded. 2026-10-21 to 2026-10-21.Scrying (screenshot)
Try this loadout
node "<spell-report-skill-directory>/scripts/spell-report.mjs" trial --spell anthropic-frontend-design --quest illusionist-signup-form --hero claude-code --weapon 'claude-sonnet-5-5' --charge medium --cast invoked --control

Recorded with quest v4 and spell commits anthropic-frontend-design@dbd4588f9e1033efb41dad4bef2f7947c8993d44. How to run it

Illusionist: booking form repairQuest v4100%2 of 2Unarmed: 87% (13 of 15)34%+13 ppvs Unarmed0 of 20%Unarmed: 0 of 1521m 12sUnarmed: 1m 6s2,275 Unarmed: 1,761Not reportedUnarmed: 12.2k+128 / -70Unarmed: +114 / -610%Hero: Claude Code 2.1.305; weapon (model): claude-sonnet-5-5; charge (effort): medium; arena: sealed; ambient cast (the agent chose).
macOS 27.0.1, arm64. Curator.
0 mishaps excluded. 2026-10-21 to 2026-10-21.Scrying (screenshot)
Try this loadout
node "<spell-report-skill-directory>/scripts/spell-report.mjs" trial --spell anthropic-frontend-design --quest illusionist-signup-form --hero claude-code --weapon 'claude-sonnet-5-5' --charge medium --cast ambient --control

Recorded with quest v4 and spell commits anthropic-frontend-design@dbd4588f9e1033efb41dad4bef2f7947c8993d44. How to run it

Scrying (screenshots of runs)

The latest run of each setup. Local paths, names and ids are blurred; credentials are removed.

Scrying (screenshot) of a fizzled run of Illusionist: pricing plan switcher with Anthropic Frontend Design, Claude CodeScrying (screenshot) of a fizzled run of Illusionist: pricing plan switcher with Anthropic Frontend Design, Claude CodeScrying (screenshot) of a fizzled run of Illusionist: pricing plan switcher with Anthropic Frontend Design, Claude CodeScrying (screenshot) of a cleared run of Illusionist: pricing plan switcher with Anthropic Frontend Design, Claude Code
Explore the quests, full results and trial method

This spell has no recorded sessions in the curator's logs. Tried it? Send a spell report.