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

Annotations already declare readOnlyHint=true, idempotentHint=true, and openWorldHint=false, so the safety profile is covered. The description adds nothing beyond that basic read semantics: no note on missing/404 behavior, error handling, or lookup constraints. It does not contradict the annotations, but it provides no extra behavioral context.

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 front-loaded sentence with no wasted words. It is appropriately terse for a simple lookup tool, though the absence of any distinction or usage clause leaves it slightly under-structured relative to the sibling set.

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 low complexity, full schema descriptions, annotations, and an output schema, the description is minimally sufficient to invoke the tool. It omits how to obtain the required IDs and when to prefer this over subsystems_list, but those gaps are partially mitigated by the schema and sibling names.

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 both required UUID parameters are fully documented in the input schema. The description says 'by id,' which loosely maps to subsystem_id but does not clarify why project_id is also required or add any format/usage nuance. Baseline 3 is appropriate when the schema carries the parameter documentation.

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 gives a specific verb and resource ('Get a subsystem'), and the singular 'a subsystem by id' hints at a single-record fetch rather than a list. However, it never explicitly differentiates itself from siblings like subsystems_list or subsystems_create. It is clear but not sibling-aware.

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 when-to-use guidance, no mention of alternatives such as subsystems_list for discovering IDs, and no prerequisites. The agent must infer entirely from the sibling names and schema.

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