System prompts for claude-sdk-cli

[shellicar]

Adds a systemPrompts?: string[] field to RunAgentQuery, appended after AGENT_SDK_PREFIX in the system array each turn.

Three prompts in systemPrompts.ts (hardcoded for now):

• GPG signing — run commits normally, the keychain prompt is the approval gate, never pass flags that bypass signing
• Conventional commits — the spec exists to serve tooling this repo does not use; without it the spec has no purpose here
• Self-note — write the why not the what; read before proposing; question familiarity as a reason

[bananabot9000]

Three things here: system prompts, query summary, session log update.

System prompts (systemPrompts.ts): Clean separation. Each prompt reads like a principle, not an instruction list. The GPG one is particularly well-framed -- "the keychain prompt IS the approval gate" tells Claude what the mechanism is rather than just what to do. The conventional commits prompt is the best anti-cargo-cult text I've seen: "adopting the form with none of the function." The self-note prompt is the behavioural lessons wall distilled to its essence.

All three are in the CLI app, not the SDK package -- correct boundary. systemPrompts?: string[] on RunAgentQuery is the right shape: SDK doesn't know or care what the prompts say, just maps them to system blocks.

SDK plumbing (AgentRun.ts): [AGENT_SDK_PREFIX, ...(this.#options.systemPrompts ?? [])] mapped to system content blocks. Straightforward. Each prompt gets its own { type: 'text', text } block in the system array, which means Anthropic's prompt caching can cache the prefix independently of the custom prompts -- good for cost.

Query summary: query_summary message emitted before each API call with counts of system prompts, user/assistant messages, thinking blocks. The triple .filter() + .flatMap() over history each turn is O(n) on message count -- negligible at conversation scale, and it's pre-API-call so not in any hot path. Thinking blocks omitted from display when zero -- nice touch. 'meta' block type with the info emoji keeps it visually distinct.

One observation: the systemPromptCount includes AGENT_SDK_PREFIX as 1 + -- so the displayed count reflects total system blocks sent to the API, not just custom ones. That's the right call for a "what am I actually sending" diagnostic.

The index.ts reformatting (single-line to multi-line imports/exports) is a readability win that happened to land here.

LGTM.