Fetch a specific WeChat message's content by session ID and stable local ID, with paginated reads to retrieve long messages without character truncation.
按单个会话和稳定localId有界回查眼提供的content字段；不做字符截断，可用nextOffset续读。
| Name | Required | Description | Default |
|---|---|---|---|
| offset | No | ||
| local_id | Yes | ||
| page_size | No | ||
| scan_limit | No | ||
| session_id | Yes |
Changes observed during successful MCP inspections.
v4.1.8Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, destructiveHint=false, openWorldHint=false, so safety is covered. The description adds genuinely non-redundant behavior: content is returned without character truncation and can be resumed via nextOffset, which tells the agent to expect paged, complete content rather than a clipped snippet.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
A single dense sentence with no filler, which is appropriately sized. However it leads with the mechanism (bounded re-query) rather than the action, and contains a garbled phrase ('眼提供') that obscures what content is being returned.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a 5-parameter tool with no output schema and no parameter descriptions, the definition is too thin: scan_limit's role, page_size limits, and the relationship between offset and nextOffset are never explained. The only return-related information is that a content field comes back untruncated.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 0%, so the description must carry all five parameters, but it only addresses session_id, local_id and (implicitly) offset via nextOffset. page_size and scan_limit are left entirely unexplained, and the description does not say what nextOffset maps to in the schema.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
States a specific action (bounded re-query / fetch of a message's content) scoped to a single session and a stable localId, so the agent knows it retrieves one message rather than searching. It does not name a sibling, but the 'single session + stable localId' framing already separates it from search_messages and get_message_context.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
Usage is only implied: the mention of a stable localId hints you need a known id, but there is no when-to-use, when-not-to-use, or named alternative among the many message-reading siblings. An agent must infer the precondition that a localId was already obtained elsewhere.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.