session_statusCheck the current state of a running Claude Code session by name, session ID, or process ID to monitor progress or verify status.
Report the current state of one session, resolved by name, session id, or pid.
| Name | Required | Description | Default |
|---|---|---|---|
| session | Yes | Session name, session id (or unique prefix), or pid. |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the behavioral burden. 'Report' and 'current state' imply a read-only snapshot, but it does not disclose error behavior, exact return shape, or what happens when the session is not found. This is adequate but not thorough.
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?
The description is a single, front-loaded sentence with no redundant words. It conveys the core operation and resolution options clearly and efficiently.
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?
The tool is simple and the parameter is fully documented, but there is no output schema and the description does not hint at what status fields are returned or how this tool relates to read_transcript. It is usable, but not fully complete for all selection and invocation needs.
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?
The input schema already fully documents the single parameter, including the same name/id/pid resolution detail. The description adds no new parameter semantics beyond what the schema provides, so the 100% schema coverage baseline of 3 applies.
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?
The description clearly states a specific verb and resource: 'Report the current state of one session.' It also specifies the resolution methods (name, session id, or pid) and the singular 'one session' distinguishes it from list_sessions and other sibling tools.
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?
The phrase 'one session' sets clear context that this tool is for a targeted single-session lookup rather than enumeration, which reasonably distinguishes it from list_sessions. However, it does not explicitly name alternatives or when-not-to-use conditions, so it misses a 5.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.