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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false, and openWorldHint, so the safety profile is covered. The description adds one genuinely useful behavioral fact — that returned fields are redacted — but says nothing about pagination, error behavior, or what happens with an invalid ref.

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 tight sentence with no filler, and the key retrieval scope and the redaction caveat are front-loaded. Every word earns its place.

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 read tool with full schema coverage and clear annotations, the definition is nearly sufficient — it states the resource, the key, and that fields are redacted. With no output schema, a little more on the returned payload shape would help, but the gap is minor.

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%, so the schema already documents ref format, field filtering, instance selection, and stacktrace folding; the description's 'by ref' merely echoes the schema. Baseline 3 applies when structured data carries the parameter burden.

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 names a specific verb-action (get) and resource (one message) plus the lookup key ('by ref'), so the agent knows exactly what it retrieves. It does not, however, distinguish itself from siblings like context_around or search_logs, which also surface message content.

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?

There is no when-to-use guidance, no exclusions, and no mention of alternatives such as context_around for surrounding logs or search_logs for finding messages. The agent must infer usage purely from the name and ref semantics.

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