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get_asn1

Retrieve ASN.1 definitions from 3GPP specifications by name, or list all assignments in a spec. Ignores case and separators for flexible matching.

Instructions

Get ASN.1 definitions from the 3GPP specifications. The protocol specifications (RRC TS 38.331/36.331, NGAP TS 38.413, S1AP TS 36.413, XnAP, F1AP, LPP TS 37.355, ...) write their ASN.1 between -- ASN1START / -- ASN1STOP markers, and this tool extracts every top-level assignment from those blocks. With name, it returns the full text of that assignment — type, constant or information object — together with the specification and section that define it, so the answer can be cited. Use it when you know a type, IE or constant name and need its definition or constraints: the defining clause can be hundreds of kilobytes, which get_section can only page through. If you do not know which specification defines the name, omit spec_id — the name is resolved across every specification in the database. Matching ignores case and separators, so an IE table title like 'AMF UE NGAP ID' finds AMF-UE-NGAP-ID. With a spec_id and no name, it lists every assignment name grouped by the section that defines it. Pass version (with spec_id) to read a past version, which is downloaded and converted on first use; call list_versions first to see which versions exist.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
nameNoASN.1 assignment name (e.g. AMF-UE-NGAP-ID). Matching ignores case and separators, so an IE title like 'AMF UE NGAP ID' also resolves. Required when spec_id is omitted; with a spec_id, omit it to list every assignment name in the specification.
offsetNoStart line number (0-based, default: 0)
spec_idNoSpecification ID (e.g. TS 38.413). Omit it to look the name up across every specification in the database — use that when you do not know which specification defines the type.
versionNoSpecification version to read (e.g. 18.6.0). Also accepts an archive token (i60) or a release selector (Rel-18). Defaults to the version in the database, and requires spec_id. Use list_versions to see what exists.
max_charsNoMaximum number of characters to return (can be combined with max_lines)
max_linesNoMaximum number of lines to return (default: 200)
Behavior4/5

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

The description explains the scope of extraction (only top-level assignments from blocks between ASN1START/ASN1STOP markers), behavior with and without the name parameter, case-insensitive and separator-ignoring matching, and handling of past versions (downloaded and converted on first use). Since no annotations are provided, the description carries full burden, which it largely fulfills, though it could be more explicit about potential limitations (e.g., if the tool is destructive or read-only).

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

Conciseness4/5

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

The description is moderately concise for the amount of information conveyed, but it is somewhat lengthy (multiple sentences). It is front-loaded with the core purpose, then progressively adds details on usage modes, matching behavior, and version handling. Every sentence adds value, but some redundancy could be trimmed (e.g., explaining matching behavior both in the main description and in the parameter description).

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

Completeness4/5

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

Given the tool's complexity (6 parameters, multiple usage modes, no output schema), the description provides comprehensive guidance on how the tool behaves in different scenarios (with/without name, with/without spec_id, with version). It also addresses how to cite results and how to discover versions. The only gap is the lack of information about the return format or output structure, but since there is no output schema, the description could be more explicit about what the tool returns (e.g., structured text, markdown, etc.).

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 description coverage is 100%, so each parameter is already documented in the schema. The description adds extra context beyond the schema, such as the effect of omitting spec_id to search across all specs, the matching behavior (case-insensitive, separator-ignoring), and the fact that name is required when spec_id is omitted. It also explains the version parameter behavior and recommends list_versions. However, since schema coverage is complete, the description exceeds the baseline of 3 but does not substantially add new meaning for every parameter.

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?

The description clearly states the tool extracts ASN.1 definitions from 3GPP specifications, specifying verb ('Get', 'extracts') and resource ('ASN.1 definitions from the 3GPP specifications'). It distinguishes it from siblings like get_section by explaining that the defining clause can be hundreds of kilobytes, which get_section can only page through.

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?

The description explicitly states when to use this tool (e.g., 'Use it when you know a type, IE or constant name and need its definition or constraints') and when to use alternatives (e.g., 'the defining clause can be hundreds of kilobytes, which get_section can only page through'). It also provides guidance on omitting spec_id when the specification is unknown, and directs users to call list_versions first to see available versions.

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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