Replay serverside file and web search

[ScriptSmith]

No description provided.

[greptile-apps]

Greptile Summary

This PR adds server-side replay for web_search_call and file_search_call history items. When a follow-up turn echoes these hosted items back, Hadrian now rewrites them into the function_call + function_call_output pairs every provider accepts, replaying the retained replay_content text so the model keeps earlier results in context. A new shared driver (server_tool_history::rewrite_hosted_calls_to_function_pairs) unifies the rewrite logic previously duplicated across MCP, web search, and file search.

• New WebSearchAction struct adds the spec-required action (query + optional source URLs) and a Hadrian-extension replay_content field to WebSearchCallOutput; both fields are populated on every search and used to reconstruct the function pair on replay.
• FileSearchResultItem schema change replaces the content: Vec<FileSearchResultContent> array with a flat text: String to match OpenAI's Responses API schema; FileSearchCallOutput gains the same replay_content extension field.
• Shared rewrite driver (server_tool_history.rs) avoids allocation on the no-match fast path via a position scan, uses exact worst-case capacity, and delegates per-item conversion to each tool's closure.

Confidence Score: 4/5

Safe to merge after addressing the FileSearchResultItem.text backward-compat deserialization failure for stored results.

The FileSearchResultItem.text field has no #[serde(default)], so any stored FileSearchCallOutput persisted with include=["file_search_call.results"] (using the old content array format) will fail to deserialize after this deploy. The failure surfaces at the multi-turn boundary — exactly when the replay machinery this PR introduces is invoked — and produces a hard error rather than degraded output. Everything else in the PR is well-guarded: WebSearchCallOutput.action has #[serde(default)], replay_content on both types has #[serde(default)], and the shared driver correctly avoids allocation on the no-match path.

src/api_types/responses.rs — FileSearchResultItem.text needs #[serde(default)] for backward compatibility with stored results items.

Important Files Changed

Filename	Overview
src/api_types/responses.rs	Adds WebSearchAction/Source types, action+replay_content to WebSearchCallOutput, and migrates FileSearchResultItem from a content array to a flat text string — the text field lacks #[serde(default)], breaking deserialization of previously stored results.
src/services/server_tool_history.rs	New shared driver for 1→2 hosted-call rewrites; scans for the first match before allocating, uses exact worst-case capacity, and passes prefix through untouched — implementation is correct.
src/services/web_search_tool.rs	Adds rewrite_web_search_history before the tools early-return, enriches the web_search_call output item with action and replay_content, adds optional source URL population, and refactors format_web_search_call_output_event to take the full item.
src/services/file_search_tool.rs	Adds rewrite_file_search_history before the tools early-return and threads replay_content through build_file_search_call_output; schema change to FileSearchResultItem.text inherits the backward-compat risk from responses.rs.
src/services/mcp/preprocess.rs	Refactors rewrite_mcp_history to delegate to the shared driver, changing mcp_call_to_function_pair to take &McpCallItem — clean reduction of duplicated rewrite logic.
src/services/responses_chain.rs	Doc-comment update and a new round-trip test for web_search_call deserialization with action and replay_content fields — no logic changes.
src/services/mod.rs	Adds pub mod server_tool_history to expose the new shared driver.
scripts/openapi-conformance.py	Adds two DOCUMENTED_MISSING_FIELDS entries for the moderation field on /chat/completions and /responses — straightforward allowlist update.

Sequence Diagram

sequenceDiagram
    participant Client
    participant Hadrian
    participant Provider
    participant SearchBackend

    Note over Client,SearchBackend: Turn 1 — search executes
    Client->>Hadrian: POST /responses (web_search tool declared)
    Hadrian->>Provider: function tool "web_search" (rewritten)
    Provider-->>Hadrian: "function_call { query }"
    Hadrian->>SearchBackend: execute_search(query)
    SearchBackend-->>Hadrian: results
    Hadrian-->>Client: SSE: web_search_call item (action + replay_content stored)
    Hadrian->>Hadrian: persist response with replay_content

    Note over Client,SearchBackend: Turn 2 — history replay
    Client->>Hadrian: POST /responses (previous_response_id or manual history)
    Note right of Hadrian: input contains WebSearchCall item
    Hadrian->>Hadrian: "rewrite_web_search_history()<br/>WebSearchCall → function_call + function_call_output<br/>(replay_content as output)"
    Hadrian->>Provider: history with function pairs (provider-compatible)
    Provider-->>Hadrian: next response
    Hadrian-->>Client: SSE response

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Prompt To Fix All With AI

Fix the following 1 code review issue. Work through them one at a time, proposing concise fixes.

---

### Issue 1 of 1
src/api_types/responses.rs:767-769
The schema migration from `content: Vec<FileSearchResultContent>` to `text: String` is not backward-compatible for stored `FileSearchCallOutput` items that previously had `include=["file_search_call.results"]`. Any such item in the DB has `"content": [{"type":"text","text":"..."}]` and no `"text"` key. Because `text` carries no `#[serde(default)]`, serde will fail with "missing field `text`" when deserializing those items, causing the entire `FileSearchCallOutput` — and therefore the multi-turn input payload — to fail. The struct doc-comment also explicitly says "each field is optional in the spec", so the spec allows omitting `text`, yet the Rust type treats it as required. Adding `#[serde(default)]` yields an empty string for old items rather than a panic, matching the same degradation strategy used for `replay_content`.

```suggestion
    /// The text retrieved from the file. OpenAI's Responses API uses a flat
    /// string here (unlike the Assistants API's typed `content` array).
    #[serde(default)]
    pub text: String,
```

_{Reviews (5): Last reviewed commit: "Review fixes" | Re-trigger Greptile}

[ScriptSmith]

@greptile-apps

[ScriptSmith]

@greptile-apps

[greptile-apps]

The schema migration from content: Vec<FileSearchResultContent> to text: String is not backward-compatible for stored FileSearchCallOutput items that previously had include=["file_search_call.results"]. Any such item in the DB has "content": [{"type":"text","text":"..."}] and no "text" key. Because text carries no #[serde(default)], serde will fail with "missing field text" when deserializing those items, causing the entire FileSearchCallOutput — and therefore the multi-turn input payload — to fail. The struct doc-comment also explicitly says "each field is optional in the spec", so the spec allows omitting text, yet the Rust type treats it as required. Adding #[serde(default)] yields an empty string for old items rather than a panic, matching the same degradation strategy used for replay_content.

Suggested change

	/// The text retrieved from the file. OpenAI's Responses API uses a flat
	/// string here (unlike the Assistants API's typed `content` array).
	pub text: String,
	/// The text retrieved from the file. OpenAI's Responses API uses a flat
	/// string here (unlike the Assistants API's typed `content` array).
	#[serde(default)]
	pub text: String,

Prompt To Fix With AI

This is a comment left during a code review.
Path: src/api_types/responses.rs
Line: 767-769

Comment:
The schema migration from `content: Vec<FileSearchResultContent>` to `text: String` is not backward-compatible for stored `FileSearchCallOutput` items that previously had `include=["file_search_call.results"]`. Any such item in the DB has `"content": [{"type":"text","text":"..."}]` and no `"text"` key. Because `text` carries no `#[serde(default)]`, serde will fail with "missing field `text`" when deserializing those items, causing the entire `FileSearchCallOutput` — and therefore the multi-turn input payload — to fail. The struct doc-comment also explicitly says "each field is optional in the spec", so the spec allows omitting `text`, yet the Rust type treats it as required. Adding `#[serde(default)]` yields an empty string for old items rather than a panic, matching the same degradation strategy used for `replay_content`.

```suggestion
    /// The text retrieved from the file. OpenAI's Responses API uses a flat
    /// string here (unlike the Assistants API's typed `content` array).
    #[serde(default)]
    pub text: String,
```

How can I resolve this? If you propose a fix, please make it concise.