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

Annotations already declare readOnlyHint=false, destructiveHint=false, openWorldHint=false. The description adds real value beyond them: partial-update semantics ('Only fields supplied are changed') and an explicit non-writable boundary (bank/tax-ID details are not MCP-writable). It stops short of stating auth requirements or whether the call returns the updated profile.

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 tight sentences: purpose, scope, then mutation semantics and exclusion. The distinctive scope constraint is front-loaded and every sentence earns its place with no restatement of the schema.

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 mutation tool with annotations covering the safety profile and no output schema (so return values need not be described), the description covers scope, partial-update behavior, and write exclusions. The remaining gap is the under-documented vatNumber/businessNumber params at 25% schema coverage.

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 25% (only entityAccount is documented), so the description must compensate. It names three of the four fields (business name, VAT number, business number) but does not explain the vatNumber vs businessNumber distinction, nor does it clarify the entityAccount boolean beyond the schema. Partial compensation, not full.

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 ('Update the host account's business profile') and names the concrete fields affected (legal business name, VAT/business registration numbers). It also disambiguates scope against the many stay-scoped siblings: 'Applies to the account owning the MCP agent token, not a specific stay.' An agent can distinguish it from getMyBusinessProfile and the updateStay* tools without reading any schema.

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?

The scoping sentence ('account owning the MCP agent token, not a specific stay') and the exclusion of bank/tax-ID fields give useful routing context. However, it never states when to reach for this versus the read counterpart (getMyBusinessProfile) or any prerequisite/permission gating. Usage is implied rather than spelled out.

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