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

Annotations already declare readOnlyHint, openWorldHint, and idempotentHint, covering safety. The description adds value by detailing the exact return contents (profile fields, moderation labels, pinned post AT-URI) and noting the public nature of the data. No contradiction with annotations.

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 front-loaded with the core purpose and returns a useful list of fields. It is slightly redundant (e.g., 'Handles and DIDs are interchangeable as input' duplicates the schema) but remains compact and structured.

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 read tool with an output schema available, the description covers the input format, usage context, return values, and resolution workflow. Nothing an agent needs to call it correctly is missing.

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 already explains the handle/DID formats and the note about bare names. The description repeats this without adding new parameter-specific meaning, so it stays at the baseline for high schema coverage.

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 clearly states the tool fetches a public profile by handle or DID and enumerates the returned fields (displayName, handle, DID, bio, counts, etc.). It distinguishes itself from siblings by explicitly positioning it as the first step to resolve a handle to a DID, and names bsky_search_actors as the alternative for bare names.

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 when-to-use guidance: 'Use this as the first step to resolve a handle to a DID before calling tools that require a DID or AT-URI.' It also gives a concrete exclusion and alternative: bare names without a dot are not handles — use bsky_search_actors. This leaves no ambiguity.

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