# Offer Safety Check > Decode a Chia offer1... string, classify what's being traded on each side, fetch market prices, and surface a risk report before the user takes it. Use when the user pastes an offer they were sent, asks "is this offer fair?", or wants to vet a deal before opening their wallet. Accepts offer, max_unfavourable_pct as arguments for programmatic invocation. - Skill: `spacetime-technology/offer-safety-check` (Agent Skill) - Install (CLI): `npx skillmds@latest add spacetime-technology/offer-safety-check` - Raw SKILL.md: https://api.skillmd.com/api/skills/spacetime-technology/offer-safety-check/raw - Safety review: pending - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Docs & Writing - Author: Spacetime-Technology (https://skillmd.com/u/spacetime-technology) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/spacetime-technology/offer-safety-check --- # Offer safety check You are vetting a Chia offer string for the user before they take it. Decode it locally via chia-explorer, classify both sides, fetch market prices, and produce a clear "looks fine" / "looks off" / "outright bad" verdict. Read-only. No wallet, no signing — the user takes the offer in their own wallet if they want to. This skill follows the conventions in this repo's `SKILLS.md`. Read that if anything below is unclear. ## Required capabilities - **chia-explorer** (`mcp__chia-explorer__*`) — mandatory. The `decode_offer` and `decompile_puzzle` tools do the heavy lifting; offer decoding is local (no RPC). ## Resolve inputs You need: `$offer`, `$max_unfavourable_pct`. - `$offer` — the `offer1...` bech32m string. Required. - `$max_unfavourable_pct` — how much worse than market you're willing to accept on the side you're giving up. Default `5` (5%). Set higher for less liquid CATs. Resolve: arguments → context → ask user. Strip whitespace from `$offer` (offers often get word-wrapped). If it doesn't start with `offer1`, emit `STATUS: failed`, `REASON: not an offer string`. ## Decode Decode the offer locally. Extract: - **Offered side** — what the *other* party is offering (what you'd receive). - **Requested side** — what they want from you in return. Each side is a list of assets: - XCH amounts (mojos → XCH) - CAT amounts, each with an `asset_id` - NFT(s), each with a `launcher_id` If decoding fails, emit `STATUS: failed`, `REASON: offer failed to decode`. Don't try to be heroic with a malformed string. ## Classify each asset For every CAT, identify the asset. chia-explorer's decompile/classify tools return the asset_id. Match against the small set of well-known tickers (DBX, SBX, USDS, etc.). If unmatched, call it `unknown CAT (asset_id 0x...)` and flag risk: unknown CATs can be worthless or scammy clones with deceptively similar names. For every NFT, fetch the launcher_id. Don't bulk-fetch off-chain metadata — that's slow and out of scope. Surface the launcher_id and tell the user to verify the NFT in their wallet before taking. ## Fetch market prices For each side: - **XCH** — current spot price from chia-explorer (USD). - **Known CATs** — chia-explorer does not currently price CATs. State this explicitly and leave the CAT side unvalued. Don't invent prices. - **NFTs** — same. No automatic floor price lookup. Total each side's USD value where possible. If a side contains an unknown CAT or an NFT, mark the total as "partial: includes unvalued asset". ## Compare and surface verdict Compute the imbalance from the user's perspective (assume the user is *taking* the offer, so they receive the offered side and give the requested side): - If both sides are fully valued in fiat: - `imbalance_pct = (requested_value - offered_value) / offered_value * 100` - Negative imbalance → user receives more than they give → favourable. - Positive imbalance → user gives more than they receive → unfavourable. - If either side has an unvalued asset, skip the percentage but still describe both sides side by side. Verdict thresholds (against `$max_unfavourable_pct`): - imbalance < 0 → `FAVOURABLE` (user benefits) - `0 ≤ imbalance ≤ max_unfavourable_pct` → `NEUTRAL` - imbalance > `max_unfavourable_pct` → `UNFAVOURABLE` (recommend declining) Risk flags (add any that apply): - `unknown_cat` — at least one CAT on either side has an unrecognised asset_id. - `nft_present` — an NFT is on either side; user must verify launcher_id matches the expected collection. - `large_amount` — total value on a fully-priced side exceeds 1000 XCH equivalent. - `multi_asset_side` — three or more distinct assets on a single side. Common in dump-bundling scams. - `decoded_but_unverifiable` — at least one asset's puzzle could be decoded but classification was ambiguous. ## Compose the report Plain-text report, surfaced inline in the conversation. Don't push to a channel — this is interactive. ``` Offer safety check Verdict: UNFAVOURABLE (you'd give 12.3% more than you receive) Risk flags: unknown_cat, multi_asset_side YOU RECEIVE (the offered side) + 1.000 XCH ~$50.00 + 500 unknown CAT (asset_id 0xabc...123) unpriced YOU GIVE (the requested side) - 1.200 XCH ~$60.00 (rounded) - 1 NFT launcher 0xdef...456 unpriced NOTES - Unknown CAT on the offered side. Don't take unless you've verified the asset_id matches the project you think it does. Names can be spoofed; asset_ids cannot. - NFT on the requested side. Confirm in your wallet that this is the launcher you intend to give up. - You handle the trade in your wallet — this check does not sign. ``` ## Hard rules - **Read-only.** Never take the offer. Never call any wallet MCP. Just report. - **Asset_id and launcher_id are truth.** Names and tickers can be spoofed; identifiers cannot. Always show the full id (truncated for readability, full on request). - **Unpriced ≠ valueless.** Don't tell the user a CAT is worthless because you can't price it. Just say "unpriced". - **No advice on whether to take.** Verdict is mechanical (above or below the imbalance threshold). The user decides. ## Recovery patterns - **Decode fails.** Report failure with the verbatim error. Common cause: truncated paste. - **Price tool fails.** Skip fiat valuations; render the asset list anyway. Emit `STATUS: partial`. - **Multi-NFT or multi-CAT offer.** Render every asset. Don't summarise away detail; the user needs to see what's actually in the offer. ## Output ``` STATUS: success | partial | failed | aborted VERDICT: FAVOURABLE | NEUTRAL | UNFAVOURABLE | UNPRICEABLE IMBALANCE_PCT: OFFERED_SIDE_USD: | none REQUESTED_SIDE_USD: | none RISK_FLAGS: ARTIFACT: none REASON: ```