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

Annotations already declare readOnlyHint=false, destructiveHint=false, openWorldHint=false and idempotentHint=true, so the safety and repeat-call profile is structured. The description's genuinely additive content is the auth requirement (verified-email session, no API key); the repeat-call sentence largely restates idempotentHint rather than adding new detail such as what is returned on a repeat or what happens to conflicting brand/support values.

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?

Three short sentences, front-loaded with the action, then preconditions, then repeat-call behavior. No filler and nothing buried.

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?

An output schema exists so return values need not be explained, and the nested parameter shapes are fully documented in schema. For a two-required-parameter mutation, the remaining useful facts — auth requirement, non-destructive, idempotent — are all present, though it says nothing about failure modes (e.g. unverified email) or whether a repeat returns the existing agency.

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 both nested objects carry their own descriptions (name, optional logo URL; email, owner name, optional help URL, coverage statement), so the schema does the heavy lifting. The description only gestures at 'the given brand and support details' without adding format, default, or constraint meaning beyond the schema.

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 and resource ('Registers a new agency') plus the ownership side-effect and the inputs it consumes ('brand and support details'). This clearly separates it from agency_profile_update in spirit, but it never names a sibling, so differentiation relies on inference from names alone.

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?

Gives concrete preconditions for use: a signed-in user session with a verified email, and explicitly rules out API-key auth. That is a real usage constraint rather than none, but it stops short of pointing to the sibling to use instead (e.g. an invite/accept flow or update path) when the preconditions fail.

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