Sablier Vesting Stream Cancellation

Overview

Cancel one or more Sablier Lockup vesting streams on the user's behalf as the stream sender. The skill discovers the user's sender-side streams through the Sablier indexer, drops non-cancelable and zero-refundable streams, and executes one cancel(uint256) transaction per selected stream on the resolved chain.

The function signature cancel(uint256) is unified across the full range of Lockup releases (v1.0 → v4.0), so the runbook does not dispatch on version for the call itself. The recipient still receives every token that has already vested at the moment of cancellation; only the unvested remainder returns to the sender.

This skill charges no markup. Cancellation is free at the protocol level — cancel(uint256) is non-payable on every Lockup version, so MSG_VALUE = 0 always.

This skill is a coordinator for vesting cancellation and execution routing.

Arguments

Workflow

1. Confirm product fit

1. Verify the user wants to cancel existing Sablier vesting streams as the sender.

1. If the user wants to create a vesting stream instead, route to sablier-create-vesting. If that skill is unavailable, recommend installing it with:

``bash npx skills add sablier-labs/sablier-skills --skill sablier-create-vesting ``

1. If the user wants to withdraw vested tokens (recipient action), route to sablier-withdraw-vesting. If that skill is unavailable, recommend installing it with:

``bash npx skills add sablier-labs/sablier-skills --skill sablier-withdraw-vesting ``

1. If the user wants to cancel a Flow open-ended stream instead of a vesting stream, route to sablier-cancel-open-ended-stream. If that skill is unavailable, recommend installing it with:

``bash npx skills add sablier-labs/sablier-skills --skill sablier-cancel-open-ended-stream ``

2. Check requested features

Stop and call out unsupported requests before selecting an execution path.

• Cross-chain batching is not supported. This skill cancels streams on a single chain per invocation. If the user has streams on multiple chains, run the skill again per chain.
• One stream per transaction. This skill does not use cancelMultiple. Selecting N streams produces N separate cancel(uint256) transactions and N wallet approvals — one per stream. This keeps each cancellation isolated: a revert on one stream never affects the others.
• Sender-only access. Only the stream's sender can call cancel. The runbook restricts the indexer query to streams where sender == wallet, so the wallet is always the authorized caller.
• Non-cancelable streams cannot be canceled. A stream created with cancelable: false reverts on cancel(...). The runbook drops these at discovery via isCancelable(streamId) (Multicall3-batched). If every surfaced stream is non-cancelable, stop with the message: "None of these vesting streams are cancelable — refunding is not possible. Cancellation was disabled at stream creation."
• Already-canceled or depleted streams cannot be canceled. The indexer query filters canceled: { eq: false } and depleted: { eq: false }.
• Withdrawing native tokens (ETH, POL, etc.) is not supported. Sablier streams only hold ERC-20 tokens. If the user mentions "ETH from my stream", they most likely mean WETH — confirm the token symbol before proceeding.

3. Clarify the required inputs

Use the AskUserQuestion tool to fill any missing inputs. Ask only for what is missing — never re-ask for values the user already provided.

• Wallet address. A 0x-prefixed EVM address — case is not enforced; the runbook lowercases it before querying the indexer. This is the sender that will sign each cancel transaction. Ask for this first — both chain and token can be inferred from the indexer once the wallet is known.
• Chain name. Optional. If the user does not know which chain, do not send them to an external UI — query the Sablier Streams indexer for every non-canceled, non-depleted stream where the wallet is the sender across all chains, collect the distinct chainId values, map them to chain names via the [Supported Chains](references/cli.md#supported-chains) table, and offer them as AskUserQuestion options. If exactly one chain has streams, auto-select it and tell the user. See [references/cli.md § Chain discovery](references/cli.md#chain-discovery).
• Token symbol. Optional. If the user does not know which token, query the indexer for every non-canceled, non-depleted stream on the resolved chain where the wallet is the sender, and offer the distinct token symbols as AskUserQuestion options (see [references/cli.md § Stream discovery](references/cli.md#stream-discovery)).

Do not guess or silently apply defaults for these parameters. Only proceed once all inputs are confirmed.

4. Validate chain support

1. Check whether the resolved chain is listed in the [Supported Chains](references/cli.md#supported-chains) table in the execution runbook.
2. If a chain surfaced by the indexer is not in the table, check Sablier Lockup deployments and ask the user for an RPC URL. If still unresolved, stop execution of this skill.

5. Route to execution

Hand off to [references/cli.md](references/cli.md) for stream discovery, multi-select, preview, confirmation, and per-stream broadcast. The discovery step pipes the indexer response through [scripts/filter-cancelable.sh](scripts/filter-cancelable.sh), which Multicall3-batches isCancelable(streamId) and refundableAmountOf(streamId) across every candidate into a single round trip — this drops non-cancelable streams, drops streams with nothing left to recover, and stamps .refundable (base-unit string) onto every survivor.

Resources

• Sablier Documentation
• EVM Lockup Deployments
• Sablier Indexer API
• Sablier GraphQL Schema
• Sablier Indexers Repo
• Sablier EVM Monorepo

Support

If you encounter any issues or unexpected errors with this skill, please file an issue at sablier-labs/sablier-skills.