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

Annotations declare readOnlyHint=true, and the description does not contradict this. The description adds valuable behavioral context beyond the annotation by stating the operation is 'deterministic' and enumerating the blast radius components. It also implies a safety/caution aspect with 'Run BEFORE changing it,' which is extra context not provided by the 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?

The description is a single sentence, front-loaded with the memorable 'BLAST RADIUS' metaphor, followed by a colon-separated list of contents. Every word earns its place; there is no fluff, repetition, or unnecessary 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?

Given the tool has no output schema, the description compensates by explicitly listing the categories of information returned (upstream context, siblings, dependent screens, files, code-coupled systems, pending inbox, recent activity). It also provides a clear usage trigger. The only missing piece is elaboration on parameter selection, but that is partially covered by the schema, so the description is adequate for correct invocation.

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 67%, with 'id' described as 'Preferred' and 'name' as 'If no id.' The tool description itself adds no parameter-specific semantics. 'project_id' remains undocumented in both schema and description, creating a minor gap. Overall, the schema does the heavy lifting for two of three parameters, but the description does not clarify the selection logic between them.

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 clearly identifies the tool as a 'BLAST RADIUS' analysis for a system, listing the specific types of context it returns (upstream, siblings, dependent screens/milestones, files, code-coupled systems, pending Inbox, recent activity). This is a specific verb+resource (get impact of system) that distinguishes it from sibling get_* tools like get_system or get_screen.

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 explicit usage timing: 'Run BEFORE changing it.' This tells the agent when to invoke this tool as a pre-modification assessment. While it does not explicitly name alternative tools, the context is clear enough that an agent would understand this is for impact analysis before edits, not for general system information.

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