diff --git a/open-sse/services/compression/outputStyles/catalog.ts b/open-sse/services/compression/outputStyles/catalog.ts
index 1330000d6a..a015e0ff83 100644
--- a/open-sse/services/compression/outputStyles/catalog.ts
+++ b/open-sse/services/compression/outputStyles/catalog.ts
@@ -95,6 +95,30 @@ export const OUTPUT_STYLE_CATALOG: Record<string, OutputStyle> = {
       },
     },
   },
+  // i-have-adhd (action-first output) — integrated into the output-style registry
+  // so it rides the existing production injector, like ponytail.
+  // Source: https://github.com/ayghri/i-have-adhd (MIT). The upstream skill's 10
+  // ADHD-friendly rules, adapted for proxy injection: agent-harness-specific rules
+  // (restate plan state, time estimates) reworded as conditionals so they hold for
+  // plain chat clients too.
+  "i-have-adhd": {
+    id: "i-have-adhd",
+    label: "I have ADHD (action-first)",
+    description:
+      "Action-first output: next action leads, steps numbered, one concrete next step, no preamble.",
+    levels: {
+      lite: `# I have ADHD (lite)\nLead with the action: command, path, or snippet first, prose after. Number multi-step work; each step one bounded action. End with ONE concrete next step. No preamble, no recap, no closing pleasantries. ${SHARED_BOUNDARIES}`,
+      full: `# I have ADHD — action-first output\n\nThe reader has ADHD. Shape output so an ADHD brain can act on it:\n1. Lead with the next action — command, path, or snippet first; context after, if at all.\n2. Number multi-step work; each step is one bounded action; use the fewest steps that work.\n3. End with ONE concrete next step doable in under two minutes.\n4. Suppress tangents: finish the first issue, offer the second as a separate question.\n5. In multi-turn work, restate where things stand ("step 3 of 5 done") — the reader cannot hold state between messages.\n6. When human effort is involved, estimate it in concrete units (minutes, an afternoon), never "some work".\n7. Make wins visible: state what now works and how to try it.\n8. Errors matter-of-fact: cause and fix; never "Uh oh".\n9. Cap lists at 5 items; split into "do now" vs "later" beyond that.\n10. No preamble, no recap, no closers ("Hope this helps").\nExceptions: an explicit "explain" request gets a full body (still no preamble/closer); destructive actions get confirmation first; real ambiguity gets one short clarifying question. ${SHARED_BOUNDARIES}`,
+      ultra: `# I have ADHD (ultra)\nAction first: command/path/snippet, then prose if needed. Numbered bounded steps, fewest that work. One <2-min next step at the end. No tangents — separate question. Multi-turn: restate state. Human effort: concrete time units. Wins visible. Errors: cause + fix. Lists ≤5. Zero preamble/recap/closers. Explain-requests get full body; destructive actions get confirmation; real ambiguity gets one question. ${SHARED_BOUNDARIES}`,
+    },
+    i18n: {
+      "pt-BR": {
+        lite: `# Eu tenho TDAH (lite)\nComece pela ação: comando, path ou snippet primeiro, prosa depois. Numere trabalho multi-passo; cada passo é uma ação delimitada. Termine com UMA próxima ação concreta. Sem preâmbulo, sem recap, sem despedidas. ${SHARED_BOUNDARIES}`,
+        full: `# Eu tenho TDAH — saída action-first\n\nO leitor tem TDAH. Molde a saída para que um cérebro TDAH consiga agir sobre ela:\n1. Comece pela próxima ação — comando, path ou snippet primeiro; contexto depois, se necessário.\n2. Numere trabalho multi-passo; cada passo é uma ação delimitada; use o menor número de passos que funcione.\n3. Termine com UMA próxima ação concreta executável em menos de dois minutos.\n4. Suprima tangentes: termine a primeira questão, ofereça a segunda como pergunta separada.\n5. Em trabalho multi-turno, reafirme onde as coisas estão ("passo 3 de 5 feito") — o leitor não guarda estado entre mensagens.\n6. Quando houver esforço humano, estime em unidades concretas (minutos, uma tarde), nunca "um pouco de trabalho".\n7. Torne vitórias visíveis: diga o que funciona agora e como testar.\n8. Erros de forma direta: causa e fix; nunca "Opa!".\n9. Listas com no máximo 5 itens; acima disso, divida em "agora" vs "depois".\n10. Sem preâmbulo, sem recap, sem despedidas ("Espero ter ajudado").\nExceções: pedido explícito de "explique" recebe corpo completo (ainda sem preâmbulo/despedida); ações destrutivas recebem confirmação antes; ambiguidade real recebe uma pergunta curta de esclarecimento. ${SHARED_BOUNDARIES}`,
+        ultra: `# Eu tenho TDAH (ultra)\nAção primeiro: comando/path/snippet, prosa depois se precisar. Passos numerados e delimitados, o mínimo que funcione. UMA próxima ação <2 min no fim. Sem tangentes — pergunta separada. Multi-turno: reafirme o estado. Esforço humano: unidades concretas de tempo. Vitórias visíveis. Erros: causa + fix. Listas ≤5. Zero preâmbulo/recap/despedidas. "Explique" recebe corpo completo; ação destrutiva recebe confirmação; ambiguidade real recebe uma pergunta. ${SHARED_BOUNDARIES}`,
+      },
+    },
+  },
   "terse-cjk": {
     id: "terse-cjk",
     label: "Terse CJK (文言)",
diff --git a/tests/unit/compression/i-have-adhd-catalog.test.ts b/tests/unit/compression/i-have-adhd-catalog.test.ts
new file mode 100644
index 0000000000..f56ff0f22b
--- /dev/null
+++ b/tests/unit/compression/i-have-adhd-catalog.test.ts
@@ -0,0 +1,76 @@
+/**
+ * Tests for the i-have-adhd output style — action-first prompt injection.
+ *
+ * Verifies:
+ *   - i-have-adhd is registered with lite/full/ultra levels
+ *   - i18n map exists for pt-BR with all three levels
+ *   - Each level (en and pt-BR) contains the SHARED_BOUNDARIES suffix
+ *   - Core concepts present: action-first, numbered steps, no preamble
+ *   - No locale gate (style valid under every language)
+ */
+
+import { describe, it } from "node:test";
+import assert from "node:assert/strict";
+import {
+  OUTPUT_STYLE_CATALOG,
+  outputStyleMeta,
+} from "../../../open-sse/services/compression/outputStyles/catalog.ts";
+
+const ADHD = OUTPUT_STYLE_CATALOG["i-have-adhd"];
+
+function assertString(v: unknown, label: string): asserts v is string {
+  assert.equal(typeof v, "string", `${label} must be a string`);
+}
+
+describe("i-have-adhd output style", () => {
+  it("is registered in the catalog with lite/full/ultra levels", () => {
+    assert.ok(ADHD, "i-have-adhd must be in catalog");
+    assert.equal(ADHD.id, "i-have-adhd");
+    assert.ok(ADHD.label.includes("ADHD"));
+    assertString(ADHD.levels.lite, "lite");
+    assertString(ADHD.levels.full, "full");
+    assertString(ADHD.levels.ultra, "ultra");
+  });
+
+  it("every level ends with the shared boundaries suffix", () => {
+    const shared = "Code blocks, file paths";
+    assert.ok(ADHD.levels.lite.includes(shared));
+    assert.ok(ADHD.levels.full.includes(shared));
+    assert.ok(ADHD.levels.ultra.includes(shared));
+  });
+
+  it("the full level contains the action-first core concepts", () => {
+    assert.ok(ADHD.levels.full.includes("Lead with the next action"));
+    assert.ok(/[Nn]umber/.test(ADHD.levels.full), "full mentions numbered steps");
+    assert.ok(ADHD.levels.full.includes("No preamble"));
+  });
+
+  it("has an i18n map for pt-BR with all three intensity levels", () => {
+    assert.ok(ADHD.i18n, "i18n must be defined");
+    const pt = ADHD.i18n["pt-BR"];
+    assert.ok(pt, "pt-BR must exist");
+    assertString(pt.lite, "pt-BR.lite");
+    assertString(pt.full, "pt-BR.full");
+    assertString(pt.ultra, "pt-BR.ultra");
+  });
+
+  it("each pt-BR level ends with shared boundaries", () => {
+    const shared = "Code blocks";
+    const pt = ADHD.i18n?.["pt-BR"];
+    assert.ok(pt, "pt-BR i18n must exist");
+    assert.ok(pt.lite.includes(shared), "pt-BR.lite contains shared boundaries");
+    assert.ok(pt.full.includes(shared), "pt-BR.full contains shared boundaries");
+    assert.ok(pt.ultra.includes(shared), "pt-BR.ultra contains shared boundaries");
+  });
+
+  it("pt-BR full contains Portuguese action-first terminology", () => {
+    const pt = ADHD.i18n?.["pt-BR"];
+    assert.ok(pt, "pt-BR i18n must exist");
+    assert.ok(/ação/.test(pt.full), "pt-BR.full mentions ação");
+    assert.ok(/preâmbulo/.test(pt.full), "pt-BR.full mentions preâmbulo");
+  });
+
+  it("carries no locale gate", () => {
+    assert.equal(outputStyleMeta("i-have-adhd").locale, undefined);
+  });
+});