PostHog Access: $ARGUMENTS
Single chokepoint for PostHog operations. Caller skills and rules MUST NOT call
mcp__posthog__* tools or PostHog REST directly.
Invocation Contract
operation: query project_id:<ID> payload:{...}
operation: insights project_id:<ID>
operation: persons project_id:<ID> [query:<QUERY>]
operation: events project_id:<ID> [after:<ISO>] [before:<ISO>]
Return parsed JSON in a <result> block.
Substrate Selection
Probe in order — the ordering is the shared credential-substrate-precedence
contract, not a PostHog-local choice. The first tier that is ready and
identity-matches the configured project is used; a substrate authenticated against
a different project is skipped, never used.
- Tier 1 — configured-provider substrate:
POSTHOG_PERSONAL_API_KEYbearer token against the configured PostHog host, resolved throughlisa-secrets-access. - Tier 2 — interactive MCP fallback: PostHog MCP, if available and
authenticated. Used when tier 1 is genuinely unavailable: no
POSTHOG_PERSONAL_API_KEY, no REST adapter for the operation, or a PostHog outage.
PostHog documents personal API keys and bearer authentication, and the same key works interactively and headlessly — which is why it leads. The REST tier uses:
POSTHOG_HOST=${POSTHOG_HOST:-https://app.posthog.com}
# Resolve the key through the chokepoint before giving up on the environment.
# `$POSTHOG_PERSONAL_API_KEY` is the documented fallback, not the only rung:
# without this, a project that keeps its credentials in Bitwarden, Doppler, or
# AWS has no tier 1 path at all and silently resolves through the interactive
# MCP — the exact divergence `credential-substrate-precedence` exists to remove.
read_posthog_key() {
[ -n "${POSTHOG_PERSONAL_API_KEY:-}" ] && { echo "$POSTHOG_PERSONAL_API_KEY"; return; }
#
# Ordered across trusted machine-managed substrates, ending at the installed
# package. Checkout-local paths are deliberately absent: a familiar generated
# destination is still repository-controlled executable code. The plugin
# rungs are the floor: `resolve-secret.mjs` ships beside this skill, so a rung
# pointing at it is reachable from anywhere the plugin itself is installed.
# Without one, a consumer repository that vendors none of the leading paths
# never reaches a resolver at all — the ladder exits without having asked
# anything, which is what pushed agents into improvising their own credential
# lookups. This LADDER is identical in every skill that resolves a credential
# and `credential-resolver-ladder` fails if any copy diverges. Only what
# happens AFTER the ladder may differ between them.
# Execute only machine-managed plugin/package resolvers. Checkout-local
# candidates are repository-controlled code, not trusted merely by path.
local candidates=()
if [ -n "${CLAUDE_PLUGIN_ROOT:-}" ]; then
candidates+=("$CLAUDE_PLUGIN_ROOT/skills/lisa-secrets-access/scripts/resolve-secret.mjs")
fi
if [ -n "${PLUGIN_ROOT:-}" ]; then
candidates+=("$PLUGIN_ROOT/skills/lisa-secrets-access/scripts/resolve-secret.mjs")
fi
# Last rung deliberately needs no environment variable: an agent that was
# never handed a plugin root still has the installed package to fall back on.
candidates+=(node_modules/@codyswann/lisa/plugins/lisa/skills/lisa-secrets-access/scripts/resolve-secret.mjs)
local resolver
local tried=()
for resolver in "${candidates[@]}"; do
tried+=("$resolver")
if [ -f "$resolver" ]; then
local via_lisa
via_lisa=$(node "$resolver" get POSTHOG_PERSONAL_API_KEY 2>/dev/null) \
&& [ -n "$via_lisa" ] && { echo "$via_lisa"; return; }
# Empty/error means this substrate had no answer; try the next trusted one.
fi
done
# Name every path. A bare `return 1` sends the next reader hunting for a
# resolver they cannot see the absence of; the enumeration turns that into a
# seconds-long diagnosis. Paths and store coordinates only — never any
# resolved value, on any path.
echo "Error: could not resolve POSTHOG_PERSONAL_API_KEY through lisa-secrets-access." >&2
echo "Tried, in order (relative paths are from $PWD):" >&2
printf ' %s\n' "${tried[@]}" >&2
return 1
}
posthog_api() {
local path="$1"
local method="${2:-GET}"
local body="${3:-}"
local key
key=$(read_posthog_key) || {
echo "Error: no PostHog key. Set POSTHOG_PERSONAL_API_KEY, or store it as" >&2
echo "POSTHOG_PERSONAL_API_KEY in this project's secrets provider." >&2
return 1
}
local args=(-sS -X "$method" -H "Authorization: Bearer $key")
[ -n "$body" ] && args+=(-H "Content-Type: application/json" --data-binary "$body")
curl "${args[@]}" "${POSTHOG_HOST%/}/api${path}"
}
If neither tier works, fail with:
Error: no PostHog access substrate available. Authenticate the PostHog MCP or set POSTHOG_PERSONAL_API_KEY.
Mutation boundary
Every operation in the Invocation Contract is read-only — analytics
retrieval. query is an HTTP POST, but it reads: it submits a query body and
changes no PostHog state. So the credential-substrate-precedence guarded
fallback for mutating operations (write, read back, assert the tenant from the
response, roll back on mismatch) is not engaged here, and a failed tier is
simply skipped. Adding a genuinely mutating operation — creating an insight,
editing a feature flag — pulls that protocol in: a write of unknown outcome MUST
reconcile by read-back before any retry.
Invariants
- Tier order is
credential-substrate-precedence:POSTHOG_PERSONAL_API_KEYfirst, the PostHog MCP as a preserved first-class fallback. Identity-match against the configured project is mandatory on every tier. - The key is resolved through
lisa-secrets-access, with the barePOSTHOG_PERSONAL_API_KEYenvironment variable as the documented fallback. Never read a second credential store directly. POSTHOG_HOSTdefaults to PostHog Cloud but can point at a self-hosted deployment.- Consumer skills do not embed PostHog REST paths.