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

Annotations already declare readOnlyHint=false, idempotentHint=true, destructiveHint=false and openWorldHint=false. The description adds substantive context beyond that: the event, endpoint, filter, and destination are immutable, so the mutation surface is confined to a label — useful reassurance that matches the non-destructive annotation.

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 sentences, no filler, with the scope constraint front-loaded and the escape hatch to the alternative workflow second. Every clause earns its place.

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 rich annotations, a full input schema, and an output schema, the description covers the remaining gaps: immutability of sibling fields and the replacement workflow. Only minor details (e.g., error behavior on unknown ID) are absent, which is acceptable given the structured fields available.

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 only 50%, but the description compensates by telling the agent to use a PLAIN name-value object, which explains the nested {type: 'PLAIN', value: ...} shape that the schema alone presents without rationale. The id parameter's exactness requirement is already covered in 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 (change display name), a specific resource (one Port OS event subscription), and a precise selector (by exact ID). It is clearly distinguishable from subscription_cancel, subscription_list, and subscription_inspect, which operate on lifecycle or listing rather than the label.

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?

Explicitly scopes the tool to display-name changes only, then names the excluded case (changing what is watched) and prescribes the alternative workflow: create a replacement monitor and cancel the old ID. An agent has no ambiguity about routing.

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