Table of Contents

Use Spec Kitty in Letta Code

Tier: partial — Spec Kitty installs Letta Code command-skill packages in 3.2, but real-session smoke evidence is not yet recorded. Citation (accessed 2026-06-02): https://docs.letta.com/letta-code/skills/

Partial-tier note

Letta Code is classified partial in the 3.2 support matrix because:

  1. The Spec Kitty installer produces command-skill packages under .agents/skills/spec-kitty.*/SKILL.md.
  2. Letta Code's skills documentation says .agents/skills/ is the preferred project-scoped skills location.
  3. A real-session smoke test for the complete Spec Kitty command set has not yet been recorded, so the row remains partial instead of supported.

Promotion to supported requires at least one documented smoke test against a real Letta Code session; the full rule is maintained in docs/development/3-2-harness-research-method.md §6.

Prerequisites

  • Spec Kitty CLI installed. See Install Spec Kitty.
  • Project initialized for this harness: 
    spec-kitty init --ai letta
  • Letta Code installed and authenticated. Follow the Letta Code documentation at https://docs.letta.com/letta-code for the current install path and authentication flow.

Where Spec Kitty installs files

Per the supported-harnesses matrix, Letta Code consumes Spec Kitty as Agent Skills. Spec Kitty installs:

  • Directory: .agents/skills/spec-kitty.<command>/
  • Files: one SKILL.md per command (spec-kitty.specify/SKILL.md, spec-kitty.plan/SKILL.md, spec-kitty.tasks/SKILL.md, spec-kitty.implement/SKILL.md, etc.).
  • Manifest: .kittify/command-skills-manifest.json records that Letta references each command-skill package.
  • Runtime ignore entry: .letta/ is added to .gitignore when Letta is configured.

The shared .agents/skills/ tree can be co-owned by Codex, Vibe, Pi, and Letta. Do not copy or edit the generated SKILL.md files manually; use spec-kitty agent config sync or spec-kitty upgrade to refresh them.

Canonical invocation

Letta Code can load a skill directly with slash syntax. For Spec Kitty command-skill packages, use the skill name as the slash command:

/spec-kitty.specify "a hello world page"
/spec-kitty.plan
/spec-kitty.tasks
/spec-kitty.implement WP01

Use /skills inside Letta Code to browse discovered skills. If the Spec Kitty skills do not appear after changing files, ask Letta to refresh skills or restart the session.

Worked example

Until full smoke evidence lands, treat Letta Code as a partial-tier host and verify command behavior on a low-risk mission first:

  1. From your project root, run Letta Code.
  2. At the prompt, type: 
    /spec-kitty.specify "a hello world page"
  3. Answer the Spec Kitty interview prompts inline.
  4. When asked for a kebab-case slug, supply something short, e.g. hello-world-page.
  5. The mission spec lands at kitty-specs/hello-world-page-<mid8>/spec.md.

If Letta does not expose the command in your installed version, the artifacts remain harness-agnostic:

  1. Drive the mission lifecycle through another configured harness.
  2. The mission spec lands at kitty-specs/hello-world-page-<mid8>/spec.md on disk.
  3. Open Letta Code against the same project directory and inspect the kitty-specs/ tree as plain files.

Troubleshooting

  • No /spec-kitty.* skills inside Letta Code. Confirm .agents/skills/spec-kitty.*/SKILL.md exists, run spec-kitty agent config sync, then restart Letta Code or refresh skills.

  • Skill list shows stale content. Letta caches the discovered skill list in session memory. Refresh skills or restart the session after running spec-kitty upgrade.

  • Slash-command hosts work but Letta does not. Letta is a skill host for Spec Kitty. It reads project-local skills from .agents/skills/; it does not use the user-global slash-command directories such as ~/.claude/commands/.

Where to learn more about Letta Code

Authoritative documentation: https://docs.letta.com/letta-code/skills/ (accessed 2026-06-02). The matrix row in docs/reference/supported-harnesses.md remains the promotion tracker.

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