docs: Rename grep options

Author: aron-cf

docs/04_filesystem_interface.md

@@ -231,38 +231,61 @@ const paths = await fs.ls("/workspace/.agents/skills");
 
 ### `grep`
 
-Available on `Workspace.fs` for parity with the agent tools, and on
-`Workspace.runtime` when you want it to run inside the container (faster
-for large trees because it uses ripgrep).
+`Workspace.fs.grep` accepts this interface:
 
 ```ts
+interface GrepOptions {
+  regex?: boolean;
+  ignoreCase?: boolean;
+  context?: number;
+  limit?: number;
+  offset?: number;
+  include?: string;
+}
+
+interface WorkspaceGrepContextLine {
+  line: number;
+  text: string;
+  isMatch: boolean;
+}
+
+interface WorkspaceGrepMatch {
+  path: string;
+  line: number;
+  text: string;
+  context?: WorkspaceGrepContextLine[];
+}
+
 grep(
   pattern: string,
-  path:    string,
-  options?: { ignoreCase?: boolean }
-): Promise<{ path: string; line: number; text: string }[]>
+  path: string,
+  options?: GrepOptions,
+): Promise<WorkspaceGrepMatch[]>
 ```
 
-`pattern` is a **literal substring** — not a regex, not a glob.
-`ignoreCase` lowercases both sides before comparing.
-
-`path` may be a directory **or a single file**. Directory walks return
-matches in walk order. Each result row carries:
+Matching is literal and case-sensitive by default. Set `regex: true` to
+interpret `pattern` as a regular expression and `ignoreCase: true` to ignore
+letter case. `context` adds that many lines before and after each match.
+`include` is a glob relative to a searched directory. `limit` and `offset`
+paginate matching lines.
 
-- `path` — absolute path of the matching file.
-- `line` — 1-indexed line number within that file.
-- `text` — the entire matching line (without the trailing newline), not
-  just the matched substring.
+`path` may be a directory or a single file. Directory searches return matches
+in deterministic depth-first discovery order, then line order within each
+file. Results are not globally sorted by full path.
 
 ```ts
-const hits = await fs.grep("TODO", "/workspace/src", { ignoreCase: true });
+const hits = await fs.grep("TODO", "/workspace/src", {
+  ignoreCase: true,
+  include: "**/*.ts",
+});
 for (const hit of hits) {
   console.log(`${hit.path}:${hit.line}: ${hit.text}`);
 }
 ```
 
-See [05. Shell Interface](./05_runtime_interface.md) for the container-side
-variant.
+`Workspace.runtime` exposes a narrower container-side variant that accepts only
+`ignoreCase` and treats its pattern as a literal string. See
+[05. Shell Interface](./05_runtime_interface.md) for that variant.
 
 ## Error handling
 

docs/09_tool_interface.md

@@ -168,19 +168,19 @@ The pattern is relative to `path`. `*` stays within one path segment, `**` cross
   path?: string;          // default /workspace
   query: string;
   include?: string;       // glob relative to path
-  fixedString?: boolean;  // default false
-  caseSensitive?: boolean;// default false
-  contextLines?: number;  // 0 through 10
+  regex?: boolean;        // default false
+  ignoreCase?: boolean;   // default false
+  context?: number;       // 0 through 10
   limit?: number;         // default 200, maximum 1000
   offset?: number;
 }
 ```
 
-The AI tool defaults to case-insensitive regular expressions to match Think's tool contract. Set `fixedString` when the query should be treated as plain text. Matches include path, line number, text, and optional numbered context. Invalid regular expressions return a structured error. A non-final page includes `nextOffset`.
+The AI tool defaults to literal, case-sensitive matching. Set `regex: true` to interpret `query` as a regular expression and `ignoreCase: true` to ignore letter case. Matches include path, line number, text, and optional numbered context. Invalid regular expressions return a structured error. A non-final page includes `nextOffset`.
 
 The tool passes `include`, `limit`, and `offset` through one `workspace.fs.grep` call. The storage search pages matching files and stops after the requested matches, so an included search does not build the full file or match list in the tool layer. Directory searches return matches in deterministic depth-first discovery order, then line order within each file. They are not globally sorted by full path.
 
-The lower-level `workspace.fs.grep` keeps its existing defaults: literal and case-sensitive. Its options also accept `limit`, `offset`, `include`, `contextLines`, `fixedString`, and `caseSensitive`.
+The lower-level `workspace.fs.grep` uses the same literal, case-sensitive defaults. Its options also accept `limit`, `offset`, `include`, `context`, `regex`, and `ignoreCase`.
 
 ## `write`