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

Annotations only supply destructiveHint=true, so the description carries most of the burden and does deliver: the PATCH partial-update contract ('Only the fields you pass are changed') and the API mapping (PATCH /activities/{id}) are real behavioral context. It omits permissions/auth requirements and does not warn that note replacement is irreversible, which is disclosed only in the 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 tight sentences plus a short API mapping: scope and update semantics are front-loaded, and every clause earns its place. No filler or restatement of the title.

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 5-parameter PATCH tool with no output schema, the description covers what can be changed and how partial updates behave, which is the essential call-correctness information. It leaves auth/prerequisite context and any confirmation of what the response returns unstated, a minor gap given the simple surface.

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 every parameter is already documented, including status_id's pointer to neon_list_properties name=activityStatuses. The description's field list and 'mark it completed' example add marginal framing but no syntax or format detail beyond the schema, so the baseline 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 clear verb+resource ('Change an activity's...') and enumerates the updatable fields (subject, note, status, priority), which distinguishes it from neon_update_account and the many read siblings by resource name. It stops short of explicitly contrasting with a sibling, but an agent can identify the target entity immediately.

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 description gives one usage example ('mark it completed') and implies when the tool applies, but it never states when NOT to use it, nor points to alternatives (e.g. neon_create_activity for new records, neon_get_activity for reads). Usage is implied rather than guided.

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