Polymarket Tennis
livetennisapi/livetennisapi-mcp
Build observe-only Polymarket and Kalshi tennis market tooling on the polymarket-tennis Python package (MIT) plus the Live Tennis API free tier.
Brier Score calculator for Polymarket addresses — measures prediction accuracy independent of PnL.
Install Polymarket Brier
$ npx skills add runesleo/polymarket-toolkit --skill polymarket-brier -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install runesleo/polymarket-toolkit polymarket-brier --agent claude-codeProject scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).
$ git clone --depth 1 https://github.com/runesleo/polymarket-toolkit.git skills-src && mkdir -p .claude/skills && cp -r skills-src/skills/polymarket-brier .claude/skills/polymarket-brier && rm -rf skills-srcUse ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.
Claude Code skills documentation · loads skills from .claude/skills/
Install the "polymarket-brier" agent skill from https://github.com/runesleo/polymarket-toolkit/tree/main/skills/polymarket-brier into .claude/skills/polymarket-brier/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "polymarket-brier", then confirm the skill loads.Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$skill-installer install https://github.com/runesleo/polymarket-toolkit/tree/main/skills/polymarket-brierType this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.
$ npx skills add runesleo/polymarket-toolkit --skill polymarket-brier -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install runesleo/polymarket-toolkit polymarket-brier --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/runesleo/polymarket-toolkit.git skills-src && mkdir -p .agents/skills && cp -r skills-src/skills/polymarket-brier .agents/skills/polymarket-brier && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "polymarket-brier" agent skill from https://github.com/runesleo/polymarket-toolkit/tree/main/skills/polymarket-brier into .agents/skills/polymarket-brier/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "polymarket-brier", then confirm the skill loads.Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add runesleo/polymarket-toolkit --skill polymarket-brier -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install runesleo/polymarket-toolkit polymarket-brier --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/runesleo/polymarket-toolkit.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/skills/polymarket-brier .cursor/skills/polymarket-brier && rm -rf skills-srcUse ~/.cursor/skills/ instead of .cursor/skills for a personal install.
Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/
Install the "polymarket-brier" agent skill from https://github.com/runesleo/polymarket-toolkit/tree/main/skills/polymarket-brier into .cursor/skills/polymarket-brier/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "polymarket-brier", then confirm the skill loads.Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gemini skills install https://github.com/runesleo/polymarket-toolkit.git --path skills/polymarket-brier--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.
$ npx skills add runesleo/polymarket-toolkit --skill polymarket-brier -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install runesleo/polymarket-toolkit polymarket-brier --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/runesleo/polymarket-toolkit.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/skills/polymarket-brier .gemini/skills/polymarket-brier && rm -rf skills-srcUse ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.
Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/
Install the "polymarket-brier" agent skill from https://github.com/runesleo/polymarket-toolkit/tree/main/skills/polymarket-brier into .gemini/skills/polymarket-brier/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "polymarket-brier", then confirm the skill loads.Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gh skill install runesleo/polymarket-toolkit polymarket-brierInstalls for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).
$ npx skills add runesleo/polymarket-toolkit --skill polymarket-brier -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/runesleo/polymarket-toolkit.git skills-src && mkdir -p .github/skills && cp -r skills-src/skills/polymarket-brier .github/skills/polymarket-brier && rm -rf skills-srcUse ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.
GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/
Install the "polymarket-brier" agent skill from https://github.com/runesleo/polymarket-toolkit/tree/main/skills/polymarket-brier into .github/skills/polymarket-brier/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "polymarket-brier", then confirm the skill loads.GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add runesleo/polymarket-toolkit --skill polymarket-brier -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install runesleo/polymarket-toolkit polymarket-brier --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/runesleo/polymarket-toolkit.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/skills/polymarket-brier .opencode/skills/polymarket-brier && rm -rf skills-srcUse ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.
OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/
Install the "polymarket-brier" agent skill from https://github.com/runesleo/polymarket-toolkit/tree/main/skills/polymarket-brier into .opencode/skills/polymarket-brier/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "polymarket-brier", then confirm the skill loads.OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
Facts
- Skill name
polymarket-brier- GitHub stars
- 194
- Token cost
- ~1.3k tokens
- SKILL.md length
- 517 words
- Files
- 1
- Skills in repo
- 2
- Repo updated
- First seen
- Licence
- MIT
At a glance
Brier Score calculator for Polymarket addresses — measures prediction accuracy independent of PnL.
- Works in 5 steps: Fetch Settled Positions → Determine Actual Outcome → Calculate Brier Score → …
- Business, Finance & HR work in your project
- SKILL.md covers Why Brier Score?, Trigger, Background and Input, plus 2 more sections
- Calls curl; reaches data-api.polymarket.com
What it does
Polymarket Brier is an agent skill from runesleo/polymarket-toolkit. Brier Score calculator for Polymarket addresses — measures prediction accuracy independent of PnL. Separates skilled predictors from market makers and arbitrageurs.
Its SKILL.md is about 1.3k tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.
It sits in Business, Finance & HR. It works with Polymarket and TypeScript. The repository describes itself as: CLI + AI Skills workflow for profiling Polymarket traders from an address. The licence is MIT.
When your agent uses it
- Business, Finance & HR work in your project
Example prompts
- “/polymarket-brier”
Requirements
- Pre-approved tools (allowed-tools): Bash(curl:*), Read, Write, Edit
Workflow steps
5 steps, taken from the step headings in SKILL.md.
What it can do on your machine
Read from SKILL.md and the folder at commit 4a66e7d. It shows what the files ask for, not the result of running them.
Tool permissions
Pre-approves these tools, so the agent can use them without asking each time:
Bash(curl:*)ReadWriteEdit
From allowed-tools in the SKILL.md frontmatter.
Runs code
Shell commands in SKILL.md call:
curl
From the folder's file list and the shell code blocks in SKILL.md.
Network
Hosts in commands or code, which the agent is likely to contact:
data-api.polymarket.com
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.
Context cost
Polymarket Brier loads about 1.3k tokens when it runs. Until then it costs about 45 tokens; SKILL.md has 517 words of instructions outside code blocks.
Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.
Safety
Auto-check passed
The automated check found no risky patterns in SKILL.md.
Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.
SKILL.md
The full file from runesleo/polymarket-toolkit at commit 4a66e7d, republished under its MIT licence (© runesleo). 517 words, ~1,349 tokens.
Download SKILL.mdSave it as
.claude/skills/polymarket-brier/SKILL.md (or your agent's skills folder).- name
- polymarket-brier
- description
- Brier Score calculator for Polymarket addresses — measures prediction accuracy independent of PnL. Separates skilled predictors from market makers and arbitrageurs.
- allowed-tools
- Bash(curl:*), Read, Write, Edit
- metadata.version
- 0.2.0
Polymarket Brier Score
Calculate prediction accuracy for any Polymarket address. Brier Score measures how close a trader's positions were to the actual outcomes — independent of PnL, position size, or trading strategy.
Why Brier Score?
PnL tells you who made money. Brier Score tells you who predicted correctly.
- High PnL + Poor Brier → Market maker or arbitrageur (earns spread, not predictions)
- Low PnL + Good Brier → Accurate predictor with small positions or conservative sizing
- High PnL + Good Brier → Skilled predictor who also sizes well — the real signal
Trigger
User asks about prediction accuracy, Brier score, prediction quality, forecasting skill, or "how accurate is this trader".
Background
The Brier Score is a standard metric in forecasting (used by Metaculus, Good Judgment Project, etc.).
Formula: BS = (1/N) × Σ(forecast_probability - actual_outcome)²
- 0.0 = perfect prediction (always right with 100% confidence)
- 0.25 = no skill (equivalent to random 50/50 guessing)
- 0.5+ = worse than random
Lower is better.
Input
Same as polymarket-profile — accepts 0x address, username, or profile URL.
Execution
Step 1: Fetch Settled Positions
curl -s "https://data-api.polymarket.com/positions?user={ADDRESS}&sizeThreshold=0&limit=100&offset=0"Paginate until all positions are fetched (same as polymarket-profile).
Filter to settled positions only: redeemable == true.
For each settled position, extract:
outcome: "Yes" or "No" — the side the trader heldavgPrice: the trader's average entry price = their implied probability forecastcurrentValue > 0: whether the market resolved in their favor (won) or not (lost)
Step 2: Determine Actual Outcome
For each settled position:
- If
currentValue > 0(won): the outcome the trader bet on did happen →actual = 1 - If
currentValue == 0(lost): the outcome the trader bet on did not happen →actual = 0
Step 3: Calculate Brier Score
For each settled position:
forecast = avgPrice (what they paid = their implied probability)
squared_error = (forecast - actual)²Then:
brier_score = sum(squared_error) / count(settled_positions)Step 4: Calculate Calibration Breakdown (Optional, if ≥20 settled positions)
Group positions into probability buckets by avgPrice:
| Bucket | Range | Meaning |
|---|---|---|
| High confidence | 0.80-0.99 | "Very likely to happen" |
| Moderate | 0.60-0.79 | "Probably happens" |
| Coin flip | 0.40-0.59 | "Could go either way" |
| Contrarian | 0.01-0.39 | "Betting against the crowd" |
For each bucket:
- Count positions
- Average forecast probability
- Actual win rate (% that resolved in their favor)
- A well-calibrated trader's win rate should be close to their average forecast
Show full SKILL.md (180 more words)Show less
Step 5: Output
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
Brier Score: {ADDRESS_SHORT}
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
📊 Prediction Accuracy
Brier Score: {score} ({rating})
Settled Markets: {count}
Correct: {wins}/{total} ({win_rate}%)
📐 Calibration
| Confidence | Positions | Avg Forecast | Actual Win% | Gap |
|------------|-----------|-------------|-------------|-----|
| High | 12 | 87% | 83% | -4% |
| Moderate | 8 | 68% | 62% | -6% |
| Coin flip | 5 | 52% | 60% | +8% |
| Contrarian | 3 | 28% | 33% | +5% |
💡 Interpretation
{1-2 sentence plain language summary}
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
Generated: {timestamp} | Data: Polymarket Public APIs
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━Rating Scale
| Brier Score | Rating | Meaning |
|---|---|---|
| 0.00-0.10 | Excellent | Top-tier forecaster |
| 0.10-0.15 | Good | Consistently better than chance |
| 0.15-0.20 | Average | Some skill, room to improve |
| 0.20-0.25 | Poor | Barely better than guessing |
| 0.25+ | No skill | Worse than a coin flip |
Notes
- Brier Score requires settled positions. Accounts with mostly open positions will have a small sample size — flag this: "Based on N settled markets. Score reliability increases with more data."
- If fewer than 5 settled positions, output: "Not enough settled data for a meaningful Brier Score."
avgPriceis used as the probability forecast. This is a simplification — traders who DCA (buy at multiple prices) will have a blended avgPrice. Acceptable for v0.2.- SPLIT positions should be excluded from Brier calculation. SPLIT is a market-neutral operation (buy both sides), not a directional prediction. Identify via polymarket-profile's activity data if available, otherwise include all positions with a note.
- This score is independent of position size. A $10 bet and a $10,000 bet on the same market at the same price contribute equally. This is intentional — we're measuring prediction skill, not bankroll management.
© runesleo, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file
Files
Just SKILL.md in skills/polymarket-brier of runesleo/polymarket-toolkit.
Open the folder on GitHubat commit 4a66e7d
Compare with similar skills
Polymarket Brier next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.
| Skill | Stars | Used in | Tokens | Auto-check | Licence | Repo updated |
|---|---|---|---|---|---|---|
| Polymarket Brier this skillrunesleo/polymarket-toolkit | 194 | — | ~1.3k | Automated safety check: Pass | MIT | |
| Polymarket Tennislivetennisapi/livetennisapi-mcp | 152 | — | ~3k | Automated safety check: Pass | MIT | |
| Web3 PolymarketPolymarket/agent-skills | 192 | 1 repos | ~2k | Automated safety check: Pass | None | |
| Digital Oraclekomako-workshop/digital-oracle | 878 | — | ~5.9k | Automated safety check: Pass | MIT | |
| Polyclawchainstacklabs/polyclaw | 359 | 1 repos | ~2k | Automated safety check: Pass | Apache-2.0 | |
| Polymarket TradingBlockRunAI/ClawRouter | 6.6k | — | ~1.4k | Automated safety check: Pass | MIT |
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A skill your agent uses when the user wants to actually PLACE, manage, or redeem bets on Polymarket (not just read odds — that's the blockrunpredexon data tools).
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Questions about Polymarket Brier
What does Polymarket Brier do?
Brier Score calculator for Polymarket addresses — measures prediction accuracy independent of PnL. Polymarket Brier is an agent skill from runesleo/polymarket-toolkit. Brier Score calculator for Polymarket addresses — measures prediction accuracy independent of PnL.
When should I use Polymarket Brier?
Polymarket Brier fits situations like: business, Finance & HR work in your project.
How do I install Polymarket Brier in Claude Code?
Run `npx skills add runesleo/polymarket-toolkit --skill polymarket-brier -a claude-code`. Or copy the skill folder (skills/polymarket-brier in runesleo/polymarket-toolkit) into .claude/skills/polymarket-brier in your project. Claude Code loads it when a task matches its description.
How do I install Polymarket Brier in Codex?
Run `npx skills add runesleo/polymarket-toolkit --skill polymarket-brier -a codex`. Or copy the skill folder (skills/polymarket-brier in runesleo/polymarket-toolkit) into .agents/skills/polymarket-brier in your project. Codex loads it when a task matches its description.
Can I use Polymarket Brier in Cursor, Gemini CLI or GitHub Copilot?
Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add runesleo/polymarket-toolkit --skill polymarket-brier -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/polymarket-brier, .gemini/skills/polymarket-brier, .github/skills/polymarket-brier and .opencode/skills/polymarket-brier in your project.
What does Polymarket Brier need to run?
Going by SKILL.md and its folder, Polymarket Brier needs the command-line tools its instructions call (curl). Its frontmatter pre-approves these tools: Bash(curl:*), Read, Write, Edit.
Does Polymarket Brier access the network?
SKILL.md names 1 domain. In commands or code: data-api.polymarket.com; the agent is likely to contact it when it follows the instructions. This is read from the text; nothing was executed.
Is Polymarket Brier safe to install?
Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.
What licence does Polymarket Brier use?
Polymarket Brier is published under the MIT licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.
How many tokens does Polymarket Brier use?
About 1.3k tokens (SKILL.md is roughly 5.4k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.
What are the alternatives to Polymarket Brier?
Skills that share tags, products or a category with Polymarket Brier: Polymarket Tennis (livetennisapi/livetennisapi-mcp, 152 stars), Web3 Polymarket (Polymarket/agent-skills, 192 stars), Digital Oracle (komako-workshop/digital-oracle, 878 stars) and Polyclaw (chainstacklabs/polyclaw, 359 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains Polymarket Brier?
runesleo (a GitHub user) maintains it in runesleo/polymarket-toolkit, which has 194 GitHub stars. The repository holds 2 skills in this directory. The repository was last updated on September 9, 2026.
Source: runesleo/polymarket-toolkit on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.