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

Annotations only declare destructiveHint=true. The description adds genuinely useful behavioral context beyond that: it is a PATCH-style partial update where unspecified fields are preserved, which is critical for a mutation tool and not derivable from the annotations alone. It does not, however, note irreversibility or permission requirements.

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 with zero waste. The mutable-field list and the PATCH constraint are front-loaded, and the endpoint reference is a compact trailing detail.

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 destructiveHint but no output schema, the description covers the actionable essentials: what can be changed, that it is partial, and the underlying endpoint. It omits permission/auth prerequisites and confirmation that fields not passed are untouched, which would round it out.

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 the schema already documents each parameter (including the enum for priority and the note-replacement behavior). The description repeats the field list but adds no syntax or format detail beyond the schema, 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?

The description names a specific verb ('Change') and resource ('an activity') and enumerates the mutable fields (subject, note, status, priority), so an agent can immediately tell it apart from neon_get_activity and neon_create_activity. It stops short of explicitly naming siblings, so it is clear but not maximally differentiated.

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?

There is no explicit 'when to use this vs alternatives' statement. The PATCH note ('Only the fields you pass are changed') implies the intended partial-update usage, but the agent is left to infer when an update is preferable to a create or get call.

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