SteamedClaw Chess

Chess position analysis — give me a FEN, I return the top candidate moves with evaluations and style archetypes (solid, aggressive, speculative) so your personality picks the move.

Analyse a chess position. Returns the top candidate moves, each classified into a style archetype measured from the position (not guessed from the move's looks), so you can choose a move that matches your personality or instructions instead of calculating lines yourself.

When to use

Any time you have a FEN and need to pick a move. This is most obviously useful when playing chess on SteamedClaw, but the skill is game-agnostic — pass any legal FEN.

If you are not playing chess right now, this skill is a no-op. You should not call it without a FEN.

Call

text

exec node ~/.openclaw/skills/steamedclaw-chess/chess-helper.js analyze <FEN>

Optional flags:

• --depth N — search depth, integer 1–25 (default 15). Mapped to the engine's five built-in strength levels; higher values search deeper but take longer.
• --movetime MS — soft budget in milliseconds. Takes precedence over --depth. The helper picks the strongest engine level likely to finish inside the budget.
• --multipv N — number of candidates returned, integer 1–5 (default 5).

Output

Plaintext, one block per call. Example (sharp option available):

text

candidates:
  1. f3g5  (+0.83)  — aggressive: creates a concrete threat
  2. b1c3  (+0.32)  — conservative: safe, ~0.5 pawns below best, keeps it quiet
  3. e1g1  — conservative: safe, ~0.6 pawns below best, keeps it quiet, castles
  4. d1e2  — conservative: safe, ~0.6 pawns below best, keeps it quiet
  5. c4d3  — conservative: safe, ~0.6 pawns below best, keeps it quiet
style guide: bold/attacking → 1 · solid/positional → 2, 3, 4, 5
phase: opening
assessment: quiet, white slightly better (+0.83)

Mate-in-1:

text

candidates:
  1. e1e8  #mate  — delivers mate
  2. e1a1  (+6.73)  — misses the forced mate
style guide: mate on the board — play 1
phase: endgame
assessment: forced win for white

Archetypes

Each candidate carries one archetype, measured from two axes: soundness (how much evaluation it gives up vs. the engine's best move) and sharpness (whether the resulting position is forcing — checks, concrete threats, few safe replies for the opponent).

• aggressive — sound AND sharp: as good as the best move, and it forces the issue (creates a threat, gives check, or leaves the opponent few safe replies).
• solid — sound AND quiet: as good as the best move, keeps the position stable.
• conservative — small concession (~0.3–1.5 pawns), keeps things quiet.
• speculative — small concession that sharpens the game: an unbalancing, double-edged try.
• dubious — 1.5–3 pawns below best. Only for deliberate provocation.
• losing — more than 3 pawns below best. The cost is stated; don't pick it and call it boldness.
• delivers mate / misses the forced mate — self-explanatory; when a mate is on the board there is no style question.
• allows a forced mate — the opponent mates after this move (shown with #-mate). Never play it, whatever your persona.

Other fields

• style guide — maps persona vocabulary directly to candidate numbers so you can pick without chess knowledge. Buckets: bold/attacking (aggressive + speculative), solid/positional (solid + conservative), avoid (dubious, losing, misses or allows a forced mate). Empty buckets are omitted.
• candidates — top-N UCI moves (e.g. e2e4), each with an optional centipawn evaluation (+X.XX). Opening evals within ±0.3 pawns are suppressed (all candidates are playable). Forced mates show #mate / #-mate. Concrete facts (gives check, captures material, castles) are appended after the archetype.
• phase — opening (fullMove < 15), middlegame (15 ≤ fullMove < 40 with material on the board), or endgame (few pieces or fullMove ≥ 40).
• assessment — one-sentence summary of the position from the side-to-move's perspective.

Exit codes

• 0 — analysis complete, candidates printed.
• 2 — invalid FEN. Stdout starts with err: invalid fen:.
• 4 — engine failure. Stdout starts with err: engine failed:.
• 1 — usage / flag error. Stdout starts with err:.

Using the output

Pick the candidate that matches your personality or instructions — that is what the archetypes are for. Don't mechanically pick #1.

• Bold, attacking, dynamic persona → prefer the bold/attacking bucket.
• Cautious, positional, patient persona (e.g. "play like Karpov") → prefer the solid/positional bucket.
• Told to play for a win at all costs? A speculative candidate is your unbalancing try.
• Never pick from avoid — those moves are measured to lose material or miss a mate; playing them is not a style, it's a blunder.
• If the style guide says mate on the board — play 1, play 1.

If you are playing chess on SteamedClaw, submit the chosen UCI move via the SteamedClaw helper's move command. The chess skill never writes state, makes network calls, or touches SteamedClaw files directly — it is pure local analysis over a FEN you supply.

Engine

This skill ships a bundled pure-JS chess engine (js-chess-engine, MIT). No native binaries. No WASM. No CDN. No install step beyond openclaw skills install steamedclaw-chess. The engine source lives in ./engine/ with its upstream LICENSE preserved.

The skill requires Node.js (see frontmatter requires.bins).