v1.14.0-outer-loop: explicit while loop replaces inference recursion

Converts the ad-hoc executeToolPhase → runAssistantTurn recursion into an
explicit while (stepNumber < effectiveCap) loop. A step is one stream-and-
tool-execute iteration; the loop terminates on non-tool finish, step-cap hit,
doom-loop, budget exhaustion, abort, or synthesis success.

MAX_STEPS = 200 hard ceiling (4x old effective limit from budget). Per-agent
steps: field in AGENTS.md frontmatter sets tighter caps (Refactorer: 5,
Architect: 20, others: unset = bounded only by MAX_STEPS). Resolution:
effectiveCap = Math.min(agent.steps ?? Infinity, MAX_STEPS).

executeToolPhase no longer recurses — returns ToolPhaseResult struct
(action: 'continue' | 'paused' | 'synthesis_done') so the caller decides
whether to continue or break. steps: 0 handled as "no tool calls allowed"
via runTextOnlyTurn (one text-only stream phase, tool calls ignored with
warn log).

Step-cap hits produce a sentinel summary (reuses cap_hit kind so
CapHitSentinel.tsx renders without frontend changes; text distinguishes
"Step limit reached" from "Tool budget exhausted"). Doom-loop check migrated
to top of loop body — same predicate, same threshold (3), break instead of
return.

step_start parts are in the schema CHECK but not emitted as message_parts —
writing before the stream phase creates a sequence-0 collision with
partsFromAssistantMessage. Structured log line emitted instead. Adversarial
review caught the collision pre-deploy.

332/332 server tests passing. No frontend changes. No schema changes.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/server/src/services/agents.ts

@@ -37,6 +37,10 @@ interface ParsedFrontmatter {
   // v1.8.2: optional per-agent tool-loop budget. Absent → inference resolves
   // from the agent's toolset at runtime.
   max_tool_calls?: number;
+  // v1.14.0: optional per-agent step cap. Absent → bounded only by MAX_STEPS
+  // (200) in the outer loop. Integer ≥ 0; steps: 0 means "no tool calls
+  // allowed" — the model responds text-only.
+  steps?: number;
 }
 
 function stripQuotes(s: string): string {
@@ -112,6 +116,21 @@ function parseFrontmatter(yaml: string): { data: ParsedFrontmatter; errors: stri
       } else {
         errors.push(`max_tool_calls must be an integer 1-100 (got "${valueRaw}")`);
       }
+    } else if (key === 'steps') {
+      // v1.14.0: per-agent step cap for the outer inference loop. Integer ≥ 0.
+      // steps: 0 means "no tool calls allowed" — model responds text-only.
+      // Non-integer or negative values are warned and ignored (falls back to
+      // MAX_STEPS ceiling), matching the max_tool_calls pattern above.
+      const n = Number(valueRaw);
+      if (Number.isInteger(n) && n >= 0) {
+        data.steps = n;
+      } else if (Number.isInteger(n)) {
+        console.warn(
+          `agents: steps ${n} is negative, ignoring (falling back to default)`,
+        );
+      } else {
+        errors.push(`steps must be a non-negative integer (got "${valueRaw}")`);
+      }
     }
     // Unknown keys silently ignored — forward-compat.
   }
@@ -204,6 +223,7 @@ function parseAgentSection(section: RawSection): Omit<Agent, 'source'> {
     tools: filteredTools,
     model: typeof fm.model === 'string' && fm.model.length > 0 ? fm.model : null,
     max_tool_calls: typeof fm.max_tool_calls === 'number' ? fm.max_tool_calls : null,
+    steps: typeof fm.steps === 'number' ? fm.steps : null,
   };
 }