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

With no annotations, the description carries the full burden and does disclose the return behavior: a list of messages classified as informational, warnings, and errors. 'Validates' also implies a non-mutating operation. It stops short of stating that nothing is written to disk or how invalid input versus schema errors are surfaced, which keeps it from a 5.

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?

Three short sentences, each doing distinct work: what it does, when to invoke it, and what comes back. The purpose is front-loaded and there is no redundant restatement of the name or title.

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?

With no output schema, the description usefully compensates by naming the return value as a message list with severity levels. Both parameters are covered by the schema. The only gap is that the tool's failure mode and any size or performance limits on schemaContent go unmentioned.

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 100%, and both parameters are fully documented in the schema including the .asn naming convention and the DEFINITIONS/END requirement. The description adds no parameter-level detail beyond that, so the baseline of 3 applies.

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 verb+resource ('Validates ASN.1 schema definitions') and adds the scope qualifier 'syntax and semantics'. The phrase 'without generating source code' implicitly separates it from the sibling compile_asn1_schema, so an agent can route between the two without opening either schema.

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?

Gives explicit trigger language: 'whenever a user asks to validate, check, or verify an ASN.1 schema', plus the negative condition 'without generating source code'. It does not name compile_asn1_schema directly as the alternative, so the routing is inferred rather than spelled out, but the condition that selects the sibling is clear.

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