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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds nothing beyond that: it does not say what the lookup returns (operands, flags, encoding, examples) or what happens when an opcode is not found, so behavioral value beyond annotations is essentially zero.

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?

A single front-loaded sentence with no filler. It is well structured, though it is arguably too terse given the tool's undocumented return shape.

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 two-parameter lookup with full schema coverage, the description is adequate. With no output schema, however, it should ideally hint at what documentation is returned (mnemonic details, operands, flags, encoding), which is a real gap.

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% — both 'opcode' and 'instruction_set' are documented in the schema, including examples for opcode and a note that instruction_set has no default. The description adds no parameter meaning on top of that, so baseline 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 ('look up documentation') and resource ('assembly instruction'), which is unambiguous against siblings like compile or list_compilers. It does not explicitly differentiate itself from any sibling, but its domain is distinct enough that confusion is unlikely.

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?

Usage is implied by the name and description — an agent can infer you call this when you need details about a mnemonic. However, there is no explicit when-to-use guidance, no mention of prerequisites, and no note about coverage limits of the instruction-set list.

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