refactor: use OpenCode session API as single source for tool parameters

lib/fetch-wrapper/formats/bedrock.ts

@@ -1,7 +1,5 @@
 import type { FormatDescriptor, ToolOutput, ToolTracker } from "../types"
 import type { PluginState } from "../../state"
-import type { Logger } from "../../logger"
-import { cacheToolParametersFromMessages } from "../../state/tool-cache"
 
 function isNudgeMessage(msg: any, nudgeText: string): boolean {
     if (typeof msg.content === 'string') {
@@ -88,28 +86,6 @@ export const bedrockFormat: FormatDescriptor = {
         return body.messages
     },
 
-    cacheToolParameters(data: any[], state: PluginState, logger?: Logger): void {
-        // Extract toolUseId and tool name from assistant toolUse blocks
-        for (const m of data) {
-            if (m.role === 'assistant' && Array.isArray(m.content)) {
-                for (const block of m.content) {
-                    if (block.toolUse && block.toolUse.toolUseId) {
-                        const toolUseId = block.toolUse.toolUseId.toLowerCase()
-                        state.toolParameters.set(toolUseId, {
-                            tool: block.toolUse.name,
-                            parameters: block.toolUse.input
-                        })
-                        logger?.debug("bedrock", "Cached tool parameters", {
-                            toolUseId,
-                            toolName: block.toolUse.name
-                        })
-                    }
-                }
-            }
-        }
-        cacheToolParametersFromMessages(data, state, logger)
-    },
-
     injectSynth(data: any[], instruction: string, nudgeText: string): boolean {
         return injectSynth(data, instruction, nudgeText)
     },

lib/fetch-wrapper/formats/gemini.ts

@@ -1,6 +1,5 @@
 import type { FormatDescriptor, ToolOutput, ToolTracker } from "../types"
 import type { PluginState } from "../../state"
-import type { Logger } from "../../logger"
 
 function isNudgeContent(content: any, nudgeText: string): boolean {
     if (Array.isArray(content.parts) && content.parts.length === 1) {
@@ -72,10 +71,6 @@ export const geminiFormat: FormatDescriptor = {
         return body.contents
     },
 
-    cacheToolParameters(_data: any[], _state: PluginState, _logger?: Logger): void {
-        // No-op: Gemini tool parameters are captured via message events in hooks.ts
-    },
-
     injectSynth(data: any[], instruction: string, nudgeText: string): boolean {
         return injectSynth(data, instruction, nudgeText)
     },

lib/fetch-wrapper/formats/openai-chat.ts

@@ -1,7 +1,5 @@
 import type { FormatDescriptor, ToolOutput, ToolTracker } from "../types"
 import type { PluginState } from "../../state"
-import type { Logger } from "../../logger"
-import { cacheToolParametersFromMessages } from "../../state/tool-cache"
 
 function isNudgeMessage(msg: any, nudgeText: string): boolean {
     if (typeof msg.content === 'string') {
@@ -79,10 +77,6 @@ export const openaiChatFormat: FormatDescriptor = {
         return body.messages
     },
 
-    cacheToolParameters(data: any[], state: PluginState, logger?: Logger): void {
-        cacheToolParametersFromMessages(data, state, logger)
-    },
-
     injectSynth(data: any[], instruction: string, nudgeText: string): boolean {
         return injectSynth(data, instruction, nudgeText)
     },

lib/fetch-wrapper/formats/openai-responses.ts

@@ -1,7 +1,5 @@
 import type { FormatDescriptor, ToolOutput, ToolTracker } from "../types"
 import type { PluginState } from "../../state"
-import type { Logger } from "../../logger"
-import { cacheToolParametersFromInput } from "../../state/tool-cache"
 
 function isNudgeItem(item: any, nudgeText: string): boolean {
     if (typeof item.content === 'string') {
@@ -66,10 +64,6 @@ export const openaiResponsesFormat: FormatDescriptor = {
         return body.input
     },
 
-    cacheToolParameters(data: any[], state: PluginState, logger?: Logger): void {
-        cacheToolParametersFromInput(data, state, logger)
-    },
-
     injectSynth(data: any[], instruction: string, nudgeText: string): boolean {
         return injectSynth(data, instruction, nudgeText)
     },

lib/fetch-wrapper/handler.ts

@@ -2,6 +2,7 @@ import type { FetchHandlerContext, FetchHandlerResult, FormatDescriptor, PrunedI
 import { type PluginState, ensureSessionRestored } from "../state"
 import type { Logger } from "../logger"
 import { buildPrunableToolsList, buildEndInjection } from "./prunable-list"
+import { syncToolParametersFromOpenCode } from "../state/tool-cache"
 
 const PRUNED_CONTENT_MESSAGE = '[Output removed to save context - information superseded or no longer needed]'
 
@@ -65,14 +66,17 @@ export async function handleFormat(
 
     let modified = false
 
-    format.cacheToolParameters(data, ctx.state, ctx.logger)
+    // Sync tool parameters from OpenCode's session API (single source of truth)
+    const sessionId = ctx.state.lastSeenSessionId
+    if (sessionId) {
+        await syncToolParametersFromOpenCode(ctx.client, sessionId, ctx.state, ctx.logger)
+    }
 
     if (ctx.config.strategies.onTool.length > 0) {
         if (format.injectSynth(data, ctx.prompts.synthInstruction, ctx.prompts.nudgeInstruction)) {
             modified = true
         }
 
-        const sessionId = ctx.state.lastSeenSessionId
         if (sessionId) {
             const toolIds = Array.from(ctx.state.toolParameters.keys())
             const alreadyPruned = ctx.state.prunedIds.get(sessionId) ?? []

lib/fetch-wrapper/types.ts

@@ -13,7 +13,6 @@ export interface FormatDescriptor {
     name: string
     detect(body: any): boolean
     getDataArray(body: any): any[] | undefined
-    cacheToolParameters(data: any[], state: PluginState, logger?: Logger): void
     injectSynth(data: any[], instruction: string, nudgeText: string): boolean
     trackNewToolResults(data: any[], tracker: ToolTracker, protectedTools: Set<string>): number
     injectPrunableList(data: any[], injection: string): boolean

lib/hooks.ts

@@ -121,13 +121,6 @@ export function createChatParamsHandler(
                                         toolCallsByName.set(toolName, [])
                                     }
                                     toolCallsByName.get(toolName)!.push(callId)
-
-                                    if (!state.toolParameters.has(callId)) {
-                                        state.toolParameters.set(callId, {
-                                            tool: part.tool,
-                                            parameters: part.input ?? {}
-                                        })
-                                    }
                                 }
                             }
                         }

lib/state/index.ts

@@ -15,9 +15,13 @@ export interface PluginState {
     lastSeenSessionId: string | null
 }
 
+export type ToolStatus = "pending" | "running" | "completed" | "error"
+
 export interface ToolParameterEntry {
     tool: string
     parameters: any
+    status?: ToolStatus
+    error?: string
 }
 
 export interface ModelInfo {

lib/state/tool-cache.ts

@@ -1,111 +1,72 @@
-import type { PluginState } from "./index"
+import type { PluginState, ToolStatus } from "./index"
 import type { Logger } from "../logger"
 
+/** Maximum number of entries to keep in the tool parameters cache */
+const MAX_TOOL_CACHE_SIZE = 500
+
 /**
- * Cache tool parameters from OpenAI Chat Completions and Anthropic style messages.
- * Extracts tool call IDs and their parameters from assistant messages.
- * 
- * Supports:
- * - OpenAI format: message.tool_calls[] with id, function.name, function.arguments
- * - Anthropic format: message.content[] with type='tool_use', id, name, input
+ * Sync tool parameters from OpenCode's session.messages() API.
+ * This is the single source of truth for tool parameters, replacing
+ * format-specific parsing from LLM API requests.
  */
-export function cacheToolParametersFromMessages(
-    messages: any[],
+export async function syncToolParametersFromOpenCode(
+    client: any,
+    sessionId: string,
     state: PluginState,
     logger?: Logger
-): void {
-    let openaiCached = 0
-    let anthropicCached = 0
+): Promise<void> {
+    try {
+        const messagesResponse = await client.session.messages({
+            path: { id: sessionId },
+            query: { limit: 100 }
+        })
+        const messages = messagesResponse.data || messagesResponse
 
-    for (const message of messages) {
-        if (message.role !== 'assistant') {
-            continue
+        if (!Array.isArray(messages)) {
+            return
         }
 
-        if (Array.isArray(message.tool_calls)) {
-            for (const toolCall of message.tool_calls) {
-                if (!toolCall.id || !toolCall.function) {
-                    continue
-                }
+        let synced = 0
 
-                try {
-                    const params = typeof toolCall.function.arguments === 'string'
-                        ? JSON.parse(toolCall.function.arguments)
-                        : toolCall.function.arguments
-                    state.toolParameters.set(toolCall.id.toLowerCase(), {
-                        tool: toolCall.function.name,
-                        parameters: params
-                    })
-                    openaiCached++
-                } catch (error) {
-                }
-            }
-        }
+        for (const msg of messages) {
+            if (!msg.parts) continue
 
-        if (Array.isArray(message.content)) {
-            for (const part of message.content) {
-                if (part.type !== 'tool_use' || !part.id || !part.name) {
-                    continue
-                }
+            for (const part of msg.parts) {
+                if (part.type !== "tool" || !part.callID) continue
 
-                state.toolParameters.set(part.id.toLowerCase(), {
-                    tool: part.name,
-                    parameters: part.input ?? {}
+                const id = part.callID.toLowerCase()
+
+                // Skip if already cached (optimization)
+                if (state.toolParameters.has(id)) continue
+
+                const status = part.state?.status as ToolStatus | undefined
+                state.toolParameters.set(id, {
+                    tool: part.tool,
+                    parameters: part.state?.input ?? {},
+                    status,
+                    error: status === "error" ? part.state?.error : undefined,
                 })
-                anthropicCached++
+                synced++
             }
         }
-    }
-
-    if (logger && (openaiCached > 0 || anthropicCached > 0)) {
-        logger.debug("tool-cache", "Cached tool parameters from messages", {
-            openaiFormat: openaiCached,
-            anthropicFormat: anthropicCached,
-            totalCached: state.toolParameters.size
-        })
-    }
-}
-
-/**
- * Cache tool parameters from OpenAI Responses API format.
- * Extracts from input array items with type='function_call'.
- */
-export function cacheToolParametersFromInput(
-    input: any[],
-    state: PluginState,
-    logger?: Logger
-): void {
-    let cached = 0
 
-    for (const item of input) {
-        if (item.type !== 'function_call' || !item.call_id || !item.name) {
-            continue
-        }
+        trimToolParametersCache(state)
 
-        try {
-            const params = typeof item.arguments === 'string'
-                ? JSON.parse(item.arguments)
-                : item.arguments
-            state.toolParameters.set(item.call_id.toLowerCase(), {
-                tool: item.name,
-                parameters: params
+        if (logger && synced > 0) {
+            logger.debug("tool-cache", "Synced tool parameters from OpenCode", {
+                sessionId: sessionId.slice(0, 8),
+                synced,
+                totalCached: state.toolParameters.size
             })
-            cached++
-        } catch (error) {
         }
-    }
-
-    if (logger && cached > 0) {
-        logger.debug("tool-cache", "Cached tool parameters from input", {
-            responsesApiFormat: cached,
-            totalCached: state.toolParameters.size
+    } catch (error) {
+        logger?.warn("tool-cache", "Failed to sync tool parameters from OpenCode", {
+            sessionId: sessionId.slice(0, 8),
+            error: error instanceof Error ? error.message : String(error)
         })
     }
 }
 
-/** Maximum number of entries to keep in the tool parameters cache */
-const MAX_TOOL_CACHE_SIZE = 500
-
 /**
  * Trim the tool parameters cache to prevent unbounded memory growth.
  * Uses FIFO eviction - removes oldest entries first.