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

With no annotations provided, the description carries the burden. It clearly states it is read-only ('Reads only; it deposits nothing'), describes the response format (bytes with header and separator), and notes it may return a refusal naming state. It doesn't cover auth or rate limits, but for a simple read tool this is sufficient.

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 longer than minimal but each sentence adds value: purpose, behavior, response format, and usage guidance. It is front-loaded with purpose and well-structured, though it could be tightened slightly without losing information.

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 single-parameter, no-output-schema tool with no annotations, the description is remarkably complete. It explains return format, usage conditions, and alternatives, leaving no critical gaps for an agent to call it correctly.

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 100% and the id parameter is fully described in the schema (including format and literal matching). The description adds no additional semantics beyond what the schema already provides, 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?

The description states a specific verb (get) and resource (relay record), clarifies it returns exact bytes, and explicitly contrasts itself with siblings (exists, list_relays). It distinguishes itself as the only tool returning a record's own bytes, making its purpose unambiguous.

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?

Provides explicit routing guidance: use exists when only checking id presence, list_relays when no id is known, and this tool for fetching bytes. This is exactly the when-to-use vs alternatives guidance expected.

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