Fetch a parsed TC39 clause as structured JSON. spec selects '262' (default) or '402'. edition defaults to 'latest'. at: '<sha>' pins to a historical main snapshot (only valid for edition='main'); omit to query the live snapshot.
| Name | Required | Description | Default |
|---|---|---|---|
| at | No | Optional historical SHA pin (hex, 4-40 chars). Only valid when edition='main'; released editions have no per-SHA history to address. | |
| id | Yes | ||
| spec | No | ||
| edition | No |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The description conveys the core read-only behavior ('fetch') and clarifies parameter constraints (e.g., at only valid for edition='main'). But without annotations, it omits details like error handling for invalid IDs or invalid SHA pins, and does not explicitly state that the operation is non-destructive.
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 concise, consisting of four short sentences. It front-loads the primary purpose and then efficiently explains the key parameters without unnecessary elaboration.
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?
Given the tool has 4 parameters, no output schema, and no annotations, the description covers parameter behavior reasonably but fails to explain the 'id' parameter and does not describe the return value beyond 'structured JSON'. This leaves the tool somewhat incomplete for an agent to use correctly without prior knowledge.
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 description adds meaning for spec (default 262 or 402), edition (default 'latest'), and at (pins to historical snapshot), which the schema only partially describes. However, the required 'id' parameter is left unexplained—the tool does not specify how to identify a clause, leaving a significant gap in usability.
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 the tool fetches a parsed TC39 clause as structured JSON, providing a specific verb and resource. This distinguishes it from siblings like clause.list (which likely lists multiple clauses) and clause.outline (which probably returns an outline structure).
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 explains parameter options for spec, edition, and at, giving some contextual guidance. However, it does not explicitly state when to use this tool over alternatives (e.g., clause.list for multiple clauses or proposal.get for proposals), nor does it mention prerequisites or common failure scenarios.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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Each tool targets a distinct function: clause operations vs. proposal queries vs. spec utilities vs. test262 search. Even the two search tools have clear differences (single vs. cross-spec).
All tools follow a consistent `domain.action` pattern using lowercase and snake_case for the action (e.g., `clause.get`, `spec.global_search`, `test262.search`). No mixing of conventions.
17 tools is appropriate for a comprehensive TC39 spec browser. Each tool serves a specific need without redundancy, covering clauses, proposals, grammar, symbols, tables, and test262.
The toolset covers the full lifecycle of exploring TC39 specifications: retrieving clauses, searching, cross-referencing, diffing editions, inspecting grammar and symbols, and querying proposals and test262.