fix: truncate webfetch content to fit context

Plugins/ZShell/Llm/tool.hpp

@@ -21,12 +21,33 @@ class LlmTool : public QObject {
 	[[nodiscard]] virtual QString description() const = 0;
 	[[nodiscard]] virtual QJsonObject parameters() const = 0;
 
+	// toolCallId identifies the call within the conversation; tools may use
+	// it to name files they write for later retrieval.
 	virtual void execute(
+		const QString& toolCallId,
 		const QJsonObject& args,
 		std::function<void(const QJsonObject& result)> done) = 0;
 	virtual void cancel();
 
 	[[nodiscard]] QJsonObject specification() const;
+
+	// The endpoint's context size in tokens (0 = unknown). Set by LlmClient.
+	[[nodiscard]] int contextSize() const { return m_contextSize; }
+	void setContextSize(int value);
+
+	// Rough cap, in characters, for tool output embedded in a tool result
+	// message. Scales with the context size so a single result cannot
+	// consume the whole window.
+	[[nodiscard]] int inlineBudgetChars() const;
+
+	// ~4 characters per token; a deliberately coarse estimate used for
+	// budgeting (never for exact accounting).
+	static constexpr int CharsPerToken = 4;
+	// Inline budget when the context size is unknown.
+	static constexpr int DefaultInlineChars = 64 * 1024;
+
+	protected:
+	int m_contextSize = 0;
 };
 
 class ToolRegistry : public QObject {
@@ -45,11 +66,15 @@ class ToolRegistry : public QObject {
 	[[nodiscard]] QJsonArray specifications() const;
 	void cancelAll();
 
+	// Propagated to every registered tool, including later ones.
+	void setContextSize(int value);
+
 	Q_SIGNALS:
 	void enabledChanged();
 
 	private:
 	bool m_enabled = true;
+	int m_contextSize = 0;
 	QList<LlmTool*> m_tools;
 };