Retrieve recent data from serial device logs. Read the last N lines from a port and filter the receive window by specifying optional start and end timestamps.
Read the last N lines of the main receive window. Optional start and end timestamps filter the range (format: yyyy-mm-dd HH:MM:SS.mmm).
| Name | Required | Description | Default |
|---|---|---|---|
| port | Yes | ||
| end_time | No | Optional end timestamp | |
| start_time | No | Optional start timestamp | |
| lines_count | No |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full burden. 'Read' implies a safe, non-mutating operation, and the timestamp format is a genuinely useful disclosure. However, it does not say whether reading consumes/advances the buffer, what happens if the port is invalid or unconnected, or how results are bounded — meaningful gaps for a buffer-reading tool.
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?
Two dense sentences with no filler; the core read behavior comes first and the optional filtering detail follows. Every clause carries information.
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?
With no output schema and no annotations, the description should say more about what a read returns and how the 'main receive window' relates to the buffers exposed by clear_data_buffers and get_buffer_status. The required port parameter is left entirely unexplained.
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?
At 50% schema coverage the description does add real value by supplying the timestamp format string, which the schema omits. But the required 'port' parameter is undocumented in both schema and description, and 'lines_count' is only obliquely referenced as 'N lines' with no mention of its default of 50.
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 verb and resource — 'Read the last N lines of the main receive window' — which an agent can distinguish from read_sent_data and read_filtered_data by the word 'main receive window.' It stops short of explicitly naming those siblings, so differentiation is implied rather than stated.
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 description implies the filtering use case ('Optional start and end timestamps filter the range') but never says when to prefer this over read_filtered_data or read_sent_data, nor any prerequisite such as an open connection. Usage is inferable but not guided.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.