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serial_output_history

Read-only

Read past serial console output without consuming it. Page losslessly with a since_seq cursor, or fetch recent text by seconds or last_bytes.

Instructions

Read past output from the broker's shared history without consuming it. For anything you must not miss, page with since_seq (start at 0; pass the returned cursor back; check dropped and has_more). Without since_seq: text by seconds or last_bytes. serial_read is drain-only.

Input Schema

NameRequiredDescriptionDefault
secondsNoIf > 0, return output from the last N seconds (prose).
max_bytesNoWith since_seq: max raw bytes in this page (default broker cap).
since_seqNoCursor from a prior history response: lossless page as JSON (cursor/dropped/has_more/chunks). Prefer this over serial_read.
last_bytesNoIf > 0, return the last N bytes of output (prose).

Output Schema

NameRequiredDescriptionDefault
modeYes
textNo
chunksNo
cursorNo
droppedNo
has_moreNo

Schema Changelog

Changes observed during successful MCP inspections.

  1. Changed1 schema field changed
    • changedOutput schema / (root)
      Previous value: -nullNew value: +{
      +  "properties": {
      +    "chunks": {
      +      "items": {
      +        "properties": {
      +          "seq_start": {
      +            "type": "integer"
      +          },
      +          "text": {
      +            "type": "string"
      +          },
      +          "timestamp": {
      +            "type": "number"
      +          }
      +        },
      +        "required": [
      +          "text",
      +          "timestamp"
      +        ],
      +        "type": "object"
      +      },
      +      "type": "array"
      +    },
      +    "cursor": {
      +      "type": "integer"
      +    },
      +    "dropped": {
      +      "type": "integer"
      +    },
      +    "has_more": {
      +      "type": "boolean"
      +    },
      +    "mode": {
      +      "enum": [
      +        "cursor",
      +        "text"
      +      ],
      +      "type": "string"
      +    },
      +    "text": {
      +      "type": "string"
      +    }
      +  },
      +  "required": [
      +    "mode"
      +  ],
      +  "type": "object"
      +}
  2. First observedv0.4.0

TDQS

A4.7/5.0
Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations cover the safety profile (readOnlyHint=true, destructiveHint=false, openWorldHint=false), but the description adds the non-obvious behavioral fact that reads do NOT consume the buffer, and exposes paging state (dropped, has_more). It omits error conditions and cursor expiry, so not a full 5.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Three tight sentences with no filler; the core non-consuming read behavior leads, followed by the paging recipe and the fallback, then the sibling contrast. Every clause carries information.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

An output schema exists so return values needn't be explained, yet the description still surfaces the meaningful response fields (cursor, dropped, has_more). For a 4-param, all-optional read tool this is complete enough to invoke correctly on the first try.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so baseline is 3, but the description adds real semantics the schema does not: since_seq must start at 0, the returned cursor must be passed back, and dropped/has_more must be checked. The seconds/last_bytes fallback condition is also stated in prose.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('Read past output from the broker's shared history') plus the differentiating trait 'without consuming it'. It explicitly contrasts itself with serial_read, which is described as drain-only, so an agent can pick between the two without opening schemas.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives explicit when-to-use routing: use since_seq paging 'for anything you must not miss' with start-at-0 and cursor-passback instructions, and fall back to seconds/last_bytes when since_seq is absent. It also names the alternative (serial_read) and its exclusive behavior (drain-only).

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.