> For the complete documentation index, see [llms.txt](https://boost.filecoin.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://boost.filecoin.io/tutorials/using-filters-for-storage-and-retrieval-deals.md).

# Using filters for storage and retrieval deals

Storage providers might demand very precise and dynamic control over a combination of deal parameters.

Boost, similarly to Lotus, provides two IPC hooks allowing you to name a command to execute for every deal before the storage provider accepts it:

* `Filter` for storage deals.
* `RetrievalFilter` for retrieval deals.

The executed command receives a JSON representation of the deal parameters, as well as the current state of the sealing pipeline, on standard input, and upon completion, its exit code is interpreted as:

* `0`: success, proceed with the deal.
* `non-0`: failure, reject the deal.

The most trivial filter rejecting any retrieval deal would be something like:\
\
`RetrievalFilter = "/bin/false"`.\
\
`/bin/false` is binary that immediately exits with a code of `1`.

[This Perl script](https://gist.github.com/ribasushi/53b7383aeb6e6f9b030210f4d64351d5/9bd6e898f94d20b50e7c7586dc8b8f3a45dab07c#file-dealfilter-pl) lets the miner deny specific clients and only accept deals that are set to start relatively soon.

You can also use a third party content policy framework like `bitscreen` by Murmuration Labs, or [CID gravity](https://cidgravity.com/):

```shell
# grab filter program
go get -u -v github.com/Murmuration-Labs/bitscreen

# add it to both filters
Filter = "/path/to/go/bin/bitscreen"
RetrievalFilter = "/path/to/go/bin/bitscreen"
```

Here is a sample JSON representation of the input sent to the deal filter:

```json
{
  "DealParams": {
    "DealUUID": "48c31c8c-dcc8-4372-a0ac-b5468eea555b",
    "IsOffline": false,
    "ClientDealProposal": {
      "Proposal": {
        "PieceCID": {
          "/": "baga6ea4seaqh5prrl6ykov4t64k6m6giijsc44dcxtdnzsp4izjakqhs7twauiq"
        },
        "PieceSize": 2147483648,
        "VerifiedDeal": false,
        "Client": "f1sw5zjcyo4mff5cbvgsgmm7uoko6gcr4tptvtkhy",
        "Provider": "f0127896",
        "Label": "bafyaa7qsgafcmalqudsaeidrunclaep6mdbipm2gjfvuosjfd6cbqd6th7bshy5hi5npxe727yjaagelucbyabasgafcmalqudsaeieapsxspo2i36no36n7yitswsxdazvziwvgj4vbp2scuxasrc6n4ejaage3r7m3saykcqeaegeavdllsbzaqcaibaaeecakrvvzam",
        "StartEpoch": 1717840,
        "EndEpoch": 2236240,
        "StoragePricePerEpoch": "1",
        "ProviderCollateral": "363196619502649",
        "ClientCollateral": "0"
      },
      "ClientSignature": {
        "Type": 1,
        "Data": "SmgcBnQE+0ZIb4zAXw7TpxLliSaliShEvX9P4+uwvxBhRDlJD+F6N3NFoNrA2y5bTeWF5aWWuL93w+SSmXFkoAA="
      }
    },
    "DealDataRoot": {
      "/": "bafyaa7qsgafcmalqudsaeidrunclaep6mdbipm2gjfvuosjfd6cbqd6th7bshy5hi5npxe727yjaagelucbyabasgafcmalqudsaeieapsxspo2i36no36n7yitswsxdazvziwvgj4vbp2scuxasrc6n4ejaage3r7m3saykcqeaegeavdllsbzaqcaibaaeecakrvvzam"
    },
    "Transfer": {
      "Type": "http",
      "ClientID": "",
      "Params": "eyJVUkwiOiJodHRwczovL2FudG8uLXB1YmxpYy1idWNrZXQtYm9vc3QuczMuZXUtY2VudHJhbC0xLmFtYXpvbmF3cy5jb20vcmFuZGZpbGVfMkdCXzAuY2FyIiwiSGVhZGVycyI6bnVsbH0=",
      "Size": 2000177948
    }
  },
  "SealingPipelineState": {
    "SectorStates": {
      "Available": 684,
      "Proving": 307,
      "Removed": 82,
      "TerminateFailed": 1,
      "TerminateWait": 5
    },
    "Workers": null
  }
}
```


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation by asking a question.

Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters:

```
GET https://boost.filecoin.io/tutorials/using-filters-for-storage-and-retrieval-deals.md?ask=<question>&goal=<user_goal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `automate deployments from our CI pipeline` lets GitBook tailor the answer to that use case.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.