Generate a structural map of symbols, headings, and keys with line ranges to read only needed slices. Use before scanning files longer than 300 lines.
Structural outline of a file: symbols/headings/keys with line ranges, so you can read only the slice you need. Use before reading any file longer than ~300 lines.
| Name | Required | Description | Default |
|---|---|---|---|
| path | Yes |
Changes observed during successful MCP inspections.
v0.1.1Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden, and it does disclose the return shape (symbols/headings/keys with line ranges) plus the fact that it enables selective reading rather than dumping content. It does not cover edge cases (unsupported/binary files, empty outlines) or confirm the non-mutating nature explicitly, so it falls short of full behavioral disclosure.
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 sentences, front-loaded with the core purpose and followed immediately by the actionable usage rule. Every clause earns its place with zero 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 simple one-parameter read tool with no output schema, the description supplies what matters: the returned structure, the intended workflow, and the usage threshold. An agent has everything needed to call it correctly; only minor file-type edge cases are unaddressed.
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 coverage is 0% and the description never explains the sole 'path' parameter, though 'of a file' weakly implies it is a file path. For a single self-evident required parameter this is minimally acceptable, but the description adds no format or constraint detail beyond the schema.
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 resource and precisely what it produces: 'Structural outline of a file: symbols/headings/keys with line ranges.' It also distinguishes itself from the read sibling by framing its output as a way to read only the slice you need, so an agent can tell it apart from read/show/list 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.
Does the description explain when to use this tool, when not to, or what alternatives exist?
'Use before reading any file longer than ~300 lines' names the trigger condition (file length threshold) and the alternative it should precede (reading). Both when-to-use and the relationship to the competing sibling are explicit, leaving nothing to inference.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.