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

Annotations declare readOnlyHint=true and openWorldHint=false, so the safe-read profile is already covered. The description exceeds that bar by disclosing the return shape, that unknown fields come back as null, the quota mechanic (profileChanges.remaining/resetsAt, calendar month UTC), and the instruction to warn the user when remaining is 0. Since it goes well past the annotation bar, this is strong, though it is largely return-value content.

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?

Front-loaded with purpose, then usage, then return semantics and quota caveat. Despite being dense, every sentence carries distinct operational value (merged payload, null unknowns, quota exhaustion warning) with no filler.

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 fully carries return-value disclosure, including the exact object shape, null semantics, and quota fields. An agent has everything needed to call it and interpret the result 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?

The tool takes no parameters, so there is nothing to document beyond the schema; a baseline 4 is appropriate. The description offers no parameter syntax because none exists.

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 ('Fetch the user's currently stored birth info') and clearly contrasts with the sibling it complements (intentions_set_birth_info). An agent immediately knows this is a read of the stored profile, distinct from the ask_* input tools.

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?

Explicitly instructs when to call it: 'Use this before intentions_set_birth_info when updating an existing profile so you can send back a complete merged payload.' Names the alternative, the condition, and the reason, plus notes 'No quota cost' which removes a reason to avoid calling it.

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