Linear: Redact Secrets from Ticket Reads

Direction

egress (tool_post_invoke)

Default

allow (transform-only, never denies)

Rego package

linear.egress.redact_secrets

App

Linear

Bundle

Engineering Stack Linear

Published

2026-10-11

Minimum gateway

1.0.0b24

Schema version

1.0.0

Checksum

sha256:acf51f9761316ce323664ddabc4a3f40d679b61dbec2226a859077f510ae7f70

What it does

Old issues are full of pasted credentials: a .env dump in a bug report, a connection string in a comment, a token in a stack trace. This policy masks them in Linear responses before the agent sees them, so they don't end up in the model's context, a chat transcript, or the next thing the agent writes.

It applies to every tool on the Linear server — issues, comments, projects, documents. JSON responses keep their structure: only string values are rewritten. If nothing matches, the response is returned byte for byte.

What gets masked

Each match is replaced with [REDACTED-SECRET]: password= / token: / api_key= style pairs, AWS access keys and secret keys, GitHub and GitLab tokens, Slack tokens, Stripe live keys, Google API keys, OpenAI-style keys, JWTs, Bearer tokens, PEM private keys, and the password part of connection strings (postgres://app:[REDACTED-SECRET]@db). Email addresses and names are left alone, so assignees, reporters, and mentions still work.

Quoted values and credential fields. key="value" and key: 'value' pairs are masked the same as unquoted ones, including JSON-style "password": "..." inside a log line or comment. In JSON responses, a string under a credential-named field (password, apiKey, client_secret, accessToken, db.password, …) is masked whatever its value looks like. Pagination cursors such as nextPageToken are left alone.

Compliance alignment

• SOC 2 CC6.7 — restricts movement of credentials into a new system (the agent's context).

Why egress

The secrets are already in Linear; the only place to stop them is on the way back to the agent. Linear itself is untouched.

Examples

Masked

{
  "input": {
    "action": "tool_post_invoke",
    "mode": "output",
    "resource": { "name": "linear-get_issue", "type": "tool" },
    "payload": { "text": [ "{\"identifier\":\"ENG-42\",\"description\":\"use AKIAIOSFODNN7EXAMPLE\"}" ] }
  }
}

The description comes back as "use [REDACTED-SECRET]".

Composition

Pair with linear/redact-secrets-writes. For customer revenue and contact fields, see linear/redact-customer-pii-egress.

Known limitations

• Server name prefix. Scope is tools whose name starts with linear. Change _in_scope if your server is registered under another name.
• Known shapes only. Secrets that don't match a listed shape pass through.
• Re-serialized JSON. When a JSON response is changed, it's returned minified with keys sorted. The content is the same.

Compliance note. This policy supports alignment with the cited framework controls on the MCP path only. No policy or bundle makes an organization compliant with any framework; web-UI, native-API, and in-app access are outside the gateway's reach by design. Validate against your own compliance program before relying on it.

Policy source (Rego)

package linear.egress.redact_secrets

# Transform-only egress policy — never denies. Masks credentials in responses
# before they enter agent context. JSON responses keep their structure: only
# string values are rewritten.
default allow := true

secret_marker := "[REDACTED-SECRET]"

# Credential shapes, applied in order. JWT and Bearer come before the generic
# key=value pair so a token is masked whole. The generic pair takes a quoted
# value ("..." or '...', on one line) or an unquoted one that stops at quotes,
# commas, and semicolons so it never eats into neighbouring text. The key may be
# quoted and carry a prefix (`"db_password": "x"`, `client.secret='x'`).
secret_patterns := [
    # JSON Web Tokens
    `eyJ[A-Za-z0-9_-]{8,}\.[A-Za-z0-9_-]{8,}\.[A-Za-z0-9_-]{8,}`,
    # Bearer tokens
    `(?i)bearer\s+[A-Za-z0-9._~+/-]{16,}=*`,
    # Generic password / token / api_key / secret in `key: value` or `key=value` form,
    # quoted or not
    `(?i)["']?[A-Za-z0-9_.-]*(?:password|passwd|secret|token|api[_-]?key|secret[_-]?key|access[_-]?key|client[_-]?secret)["']?\s*[:=]\s*(?:"[^"\r\n]+"|'[^'\r\n]+'|[^\s"'<>,;]+)`,
    # AWS access key IDs (long-term and temporary)
    `(?:AKIA|ASIA)[0-9A-Z]{16}`,
    # AWS secret access keys (40-char base64-ish, anchored near the word "aws")
    `(?i)aws(.{0,20})?(secret|access)?.{0,20}[\s:=]+[A-Za-z0-9/+=]{40}`,
    # GitHub tokens (personal, OAuth, user, server, refresh) and fine-grained PATs
    `gh[pousr]_[A-Za-z0-9]{36}`,
    `github_pat_[A-Za-z0-9_]{82}`,
    # GitLab personal access tokens
    `glpat-[A-Za-z0-9_-]{20}`,
    # Slack tokens
    `xox[baprs]-[A-Za-z0-9-]{10,}`,
    # Stripe live secret and restricted keys
    `(?:sk|rk)_live_[A-Za-z0-9]{24,}`,
    # Google API keys
    `AIza[0-9A-Za-z\-_]{35}`,
    # OpenAI-style API keys
    `sk-[A-Za-z0-9_-]{20,}`,
    # PEM private key blocks, then any stray header
    `-----BEGIN [A-Z ]*PRIVATE KEY-----[\s\S]*?-----END [A-Z ]*PRIVATE KEY-----`,
    `-----BEGIN [A-Z ]*PRIVATE KEY-----`,
]

# Passwords embedded in connection strings (postgres://user:pass@host): keep the
# scheme and user, mask the password.
conn_string_pattern := `(?i)\b([a-z][a-z0-9+.-]*://[^\s:/@"']+:)[^\s@/"']+@`

# --- Redaction of one string (Rego has no recursion, so the fold is a chain) ---

_redact(t) := out if {
    r0 := regex.replace(t, secret_patterns[0], secret_marker)
    r1 := regex.replace(r0, secret_patterns[1], secret_marker)
    r2 := regex.replace(r1, secret_patterns[2], secret_marker)
    r3 := regex.replace(r2, secret_patterns[3], secret_marker)
    r4 := regex.replace(r3, secret_patterns[4], secret_marker)
    r5 := regex.replace(r4, secret_patterns[5], secret_marker)
    r6 := regex.replace(r5, secret_patterns[6], secret_marker)
    r7 := regex.replace(r6, secret_patterns[7], secret_marker)
    r8 := regex.replace(r7, secret_patterns[8], secret_marker)
    r9 := regex.replace(r8, secret_patterns[9], secret_marker)
    r10 := regex.replace(r9, secret_patterns[10], secret_marker)
    r11 := regex.replace(r10, secret_patterns[11], secret_marker)
    r12 := regex.replace(r11, secret_patterns[12], secret_marker)
    r13 := regex.replace(r12, secret_patterns[13], secret_marker)
    out := regex.replace(r13, conn_string_pattern, concat("", ["${1}", secret_marker, "@"]))
}

# --- Redaction of every string inside a JSON value, keeping its structure ---

_is_container(x) if is_object(x)

_is_container(x) if is_array(x)

_escape_segment(seg) := replace(replace(sprintf("%v", [seg]), "~", "~0"), "/", "~1")

_pointer(path) := concat("", [concat("", ["/", _escape_segment(seg)]) | some seg in path])

# Field names that hold credentials. Compared lowercased with `_`, `-` and `.`
# removed, so apiKey, api_key, client-secret, db.password and accessToken all
# match. Pagination and sync cursors (nextPageToken, cursor_token) are not
# credentials and are left alone.
_credential_field_suffixes := {
    "password", "passwd", "passphrase", "secret", "token", "apikey",
    "accesskey", "secretkey", "privatekey", "credential", "credentials",
}

_cursor_words := {"page", "cursor", "next", "sync", "continuation"}

_credential_field(k) if {
    is_string(k)
    n := replace(replace(replace(lower(k), "_", ""), "-", ""), ".", "")
    some s in _credential_field_suffixes
    endswith(n, s)
    not _is_cursor_field(n)
}

_is_cursor_field(n) if {
    some w in _cursor_words
    contains(n, w)
}

# A non-empty string under a credential-named field is masked whole, whatever
# its value looks like. Any other string goes through the shape patterns.
_redact_at(path, v) := secret_marker if {
    count(path) > 0
    _credential_field(path[count(path) - 1])
    v != ""
} else := _redact(v)

_patches_for(doc) := [{"op": "replace", "path": _pointer(path), "value": r} |
    walk(doc, [path, v])
    is_string(v)
    r := _redact_at(path, v)
    r != v
]

# --- Scope ---

_is_egress if input.mode == "output"

_is_egress if input.action == "tool_post_invoke"

_names contains lower(object.get(object.get(input, "resource", {}), "name", ""))

_names contains lower(object.get(object.get(input, "tool_metadata", {}), "name", ""))

# Every tool on the Linear server.
_in_scope if {
    some n in _names
    startswith(n, "linear")
}

# --- Response blocks ---

_json_container(b) := doc if {
    is_string(b)
    json.is_valid(b)
    doc := json.unmarshal(b)
    _is_container(doc)
}

# JSON text with secrets: rewrite the string values, re-serialize.
_redact_block(b) := json.marshal(json.patch(doc, ps)) if {
    doc := _json_container(b)
    ps := _patches_for(doc)
    count(ps) > 0
}

# JSON text without secrets: unchanged.
_redact_block(b) := b if {
    doc := _json_container(b)
    count(_patches_for(doc)) == 0
}

# Plain text.
_redact_block(b) := _redact(b) if {
    is_string(b)
    not _json_container(b)
}

# Structured (non-string) blocks.
_redact_block(b) := json.patch(b, _patches_for(b)) if _is_container(b)

_redact_block(b) := b if {
    not is_string(b)
    not _is_container(b)
}

_text := object.get(object.get(input, "payload", {}), "text", [])

_redacted := [out | some b in _text; out := _redact_block(b)]

transform := {
    "transformed_payload": object.union(object.get(input, "payload", {}), {"text": _redacted}),
} if {
    _is_egress
    _in_scope
    is_array(_text)
    _redacted != _text
}

Canonical source: policy.md on GitHub · raw · raw on this site (.md)