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

Annotations already cover the safety profile (readOnlyHint, destructiveHint=false, openWorldHint), but the description adds meaningful non-obvious behavior: an explicit list of never-returned sensitive fields (birth data, identity/tax numbers, income, portal token). That is real disclosure the agent cannot get from annotations or schema.

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?

Two dense sentences with the returned-field inventory, sensitivity exclusions, and endpoint all front-loaded; nothing is padded. The field laundry list is long but each item carries selection value for the caller.

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 does the work of sketching the response shape and, importantly, the exclusions, which is exactly what an agent needs to reason about the result. It omits error/not-found behavior and auth requirements, but is otherwise adequate for a simple single-record fetch.

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 all three parameters are already documented in the schema, including the include and custom_fields enums. The description adds nothing about parameter syntax or format, so the baseline of 3 applies.

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 ('One contact by id') plus the exact endpoint (GET /contacts/{id}), which cleanly separates it from propstack_list_contacts. The enumeration of returned fields makes the scope unmistakable.

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?

Retrieval-by-id is self-evident, but there is no explicit guidance on when to use this versus propstack_list_contacts (e.g., for searching by name) or propstack_update_contact. Usage is implied by the id-based framing rather than stated.

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