feat(kyberforge): enforce the ADR-0020 context contract for skills and agents

Skill name+description pairs are preloaded into every session, costing
~6,200 tokens across 39 skills before any skill is invoked. The authoring
rules mandated that growth: skill-author:104 and description-quality.md:21
both required padding, while skill-author:102 (the deflating rule) had no
FAIL condition behind it.

Gates (blocking, no baseline file):
- description 250 chars SUGGESTION / 400 FAIL, measured on the folded
  YAML value
- body-only 600 words SUGGESTION / 900 FAIL, independent of the unchanged
  whole-file 2770-word / 500-line spec backstop
- every boundary-clause routing target must resolve to a real skill or
  agent; catches skill-improve, neuledge-context and gitea-labels
- agents take the description gates but deliberately no body gate; a test
  pins that absence

Vale: DescriptionOpener widened to ^This\b, new CompositionNote rule
banning architecture notes from descriptions. 10 hits, 0 false positives.

Kyberforge's own four skills retrofitted: descriptions 3,364 -> 938 chars
(-72%), bodies 8,306 -> 2,487 words (-70%), all via the apm-workflow
dispatch pattern. Fixes the skill-improve dangling route and the
agent-author misroute to manual review.

Also fixes a pre-existing false positive where any line-initial 'read '
was flagged as interactive input, which had already caused two scripts to
be rewritten around it.

Refs: ADR-0020

plugins/kyberforge/.apm/skills/agent-audit/tests/validate.bats

@@ -31,6 +31,26 @@ description: A valid agent description.
 ${extra_frontmatter}
 ---
 
+You are a test agent. When invoked, do the thing.
+EOF
+    }
+
+    # Helper: same shape as make_apm_agent, but the description is supplied
+    # verbatim — used by the ADR-0020 description-budget tests.
+    make_apm_agent_with_desc() {
+        local root="$1" name="$2" desc="$3"
+        mkdir -p "$root/.apm/agents"
+        cat > "$root/apm.yml" <<EOF
+name: test-package
+version: 0.1.0
+type: skill
+EOF
+        cat > "$root/.apm/agents/${name}.agent.md" <<EOF
+---
+name: ${name}
+description: ${desc}
+---
+
 You are a test agent. When invoked, do the thing.
 EOF
     }
@@ -607,6 +627,125 @@ EOF
     refute_output --partial "FAIL"
 }
 
+# ---------------------------------------------------------------------------
+# ADR-0020 — description budget (250 SUGGESTION / 400 FAIL)
+#
+# Agents take the SAME description gates as skills: name + description is
+# preloaded into every session identically. Agents take NO body word gate — see
+# the final test in this block, which pins that asymmetry.
+# ---------------------------------------------------------------------------
+
+@test "ADR-0020: agent description of exactly 250 chars raises no suggestion" {
+    local root="$TMPDIR/pkg"
+    make_apm_agent_with_desc "$root" "my-agent" "$(python3 -c "print('x' * 250)")"
+    run bash "$SCRIPT" "$root/.apm/agents/my-agent.agent.md"
+    assert_success
+    refute_output --partial "SUGGESTION"
+}
+
+@test "ADR-0020: agent description of 251 chars raises a SUGGESTION and still exits 0" {
+    local root="$TMPDIR/pkg"
+    make_apm_agent_with_desc "$root" "my-agent" "$(python3 -c "print('x' * 251)")"
+    run bash "$SCRIPT" "$root/.apm/agents/my-agent.agent.md"
+    assert_success
+    assert_output --partial "SUGGESTION"
+    assert_output --partial "description is 251 chars"
+}
+
+@test "ADR-0020: agent description of exactly 400 chars is a SUGGESTION, not a FAIL" {
+    local root="$TMPDIR/pkg"
+    make_apm_agent_with_desc "$root" "my-agent" "$(python3 -c "print('x' * 400)")"
+    run bash "$SCRIPT" "$root/.apm/agents/my-agent.agent.md"
+    assert_success
+    assert_output --partial "SUGGESTION"
+}
+
+@test "ADR-0020: agent description of 401 chars FAILs and exits non-zero" {
+    local root="$TMPDIR/pkg"
+    make_apm_agent_with_desc "$root" "my-agent" "$(python3 -c "print('x' * 401)")"
+    run bash "$SCRIPT" "$root/.apm/agents/my-agent.agent.md"
+    assert_failure
+    assert_output --partial "description is 401 chars"
+    assert_output --partial "400-character ADR-0020 ceiling"
+}
+
+@test "ADR-0020: agent description length is measured after YAML folding is resolved" {
+    local root="$TMPDIR/pkg"
+    mkdir -p "$root/.apm/agents"
+    cat > "$root/apm.yml" <<EOF
+name: test-package
+version: 0.1.0
+type: skill
+EOF
+    # 11 folded lines of 40 chars + 10 joining spaces = 450 characters. Read off
+    # the raw `description: >` line it is 1 character and passes.
+    {
+        echo "---"
+        echo "name: my-agent"
+        echo "description: >"
+        python3 -c "print('\n'.join(['  ' + 'x' * 40] * 11))"
+        echo "---"
+        echo ""
+        echo "You are a test agent."
+    } > "$root/.apm/agents/my-agent.agent.md"
+    run bash "$SCRIPT" "$root/.apm/agents/my-agent.agent.md"
+    assert_failure
+    assert_output --partial "description is 450 chars"
+}
+
+@test "ADR-0020: the description gate applies at project scope too" {
+    local root="$TMPDIR/project"
+    local desc
+    desc="$(python3 -c "print('x' * 401)")"
+    mkdir -p "$root/.git" "$root/.claude/agents" "$root/.github/agents"
+    cat > "$root/.claude/agents/my-agent.md" <<EOF
+---
+name: my-agent
+description: $desc
+---
+
+You are a test agent. When invoked, do the thing.
+EOF
+    cat > "$root/.github/agents/my-agent.agent.md" <<EOF
+---
+name: my-agent
+description: A valid agent description.
+---
+
+You are a test agent. When invoked, do the thing.
+EOF
+    run bash "$SCRIPT" "$root/.claude/agents/my-agent.md"
+    assert_failure
+    assert_output --partial "400-character ADR-0020 ceiling"
+}
+
+@test "ADR-0020: agents take NO body word gate — a body far over the 900-word skill ceiling passes" {
+    local root="$TMPDIR/pkg"
+    mkdir -p "$root/.apm/agents"
+    cat > "$root/apm.yml" <<EOF
+name: test-package
+version: 0.1.0
+type: skill
+EOF
+    # Deliberate asymmetry, not an oversight: a skill body is loaded into the
+    # caller's context and competes with the live conversation, while an agent
+    # body becomes the system prompt of a fresh context. ADR-0020 gates the
+    # former at 900 words and explicitly declines to gate the latter. If a body
+    # word gate is ever added here, it contradicts the ADR.
+    {
+        echo "---"
+        echo "name: my-agent"
+        echo "description: A valid agent description."
+        echo "---"
+        echo ""
+        python3 -c "print(' '.join(['word'] * 1500))"
+    } > "$root/.apm/agents/my-agent.agent.md"
+    run bash "$SCRIPT" "$root/.apm/agents/my-agent.agent.md"
+    assert_success
+    refute_output --partial "FAIL"
+    refute_output --partial "SUGGESTION"
+}
+
 @test "a bare plugin.json with no apm.yml is no longer plugin scope — falls through to project scope" {
     local root="$TMPDIR/proj-legacy-plugin-json"
     mkdir -p "$root/.git" "$root/.claude/agents" "$root/.github/agents"