Registers an existing .tape file and returns its tape_id and stats, so you can interrogate or replay previously traced computations.
Register an existing .tape file written earlier (by trace_script, by a script's own save_tape(), or downloaded from a report) and return its tape_id and stats.
| Name | Required | Description | Default |
|---|---|---|---|
| path | Yes |
Changes observed during successful MCP inspections.
v0.1.2Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full behavioral burden. It helpfully discloses the return payload ('tape_id and stats'), which is valuable given there is no output schema, but it does not state whether registration is idempotent, what happens with a nonexistent or malformed path, or whether it has side effects on persistent state.
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?
One sentence, front-loaded with the action, parenthetical provenance kept compact, and the return value stated at the end. No filler.
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 one-parameter tool this covers the essentials of what it does and what it returns, but it leaves path resolution and failure behavior unstated, both of which matter for a registration operation that presumably persists state.
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 description coverage is 0% for the single 'path' parameter, so the description must compensate. It only implies the parameter is a path to an existing .tape file; it does not say whether it is absolute or relative, whether it resolves against a source root (a sibling tool named set_source_root exists), or what file extensions are accepted.
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?
Uses a specific verb ('register') on a specific resource (an existing .tape file) and enumerates the provenance of tapes it accepts, which implicitly distinguishes it from trace_script, which produces tapes. It never explicitly contrasts with siblings, but the read/register-vs-create distinction is inferable from the text.
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 'written earlier' implies the caller should already have a tape on disk, which is a usable usage signal. However, it never says what to do instead when a tape has not been produced yet (trace_script) or when the caller wants to view an already-registered tape (inspect_tape, list_tapes).
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.