list_db2_subsystems

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

Annotations already declare readOnlyHint, idempotentHint, and openWorldHint, so the safety profile is covered. The description adds one genuinely useful behavioral fact — the DB2_LOCATION prerequisite — but says nothing about the open-world nature of the call (live subsystem discovery) or failure behavior when DB2_LOCATION is unset.

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?

One short sentence, front-loaded with the purpose and ending with the key prerequisite. No waste, though 'requires DB2_LOCATION' is terse enough to be slightly cryptic about what the variable controls.

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 simple, annotation-covered read-only lister with a single fully described optional parameter, the description plus structured fields are sufficient to call it correctly. Only the shape of a returned subsystem/location entry is left implicit, which is acceptable for a list tool with no output schema.

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% and the single optional 'environment' parameter is fully documented in the schema, so the baseline is 3. The description does not reference the environment parameter at all, adding no meaning beyond 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?

The description gives a specific verb and resource — 'List Db2 subsystems (locations)' — and scopes it to 'available via Db2 REST', which distinguishes it from sibling listers like list_cics_regions or list_environments. It stops short of explicitly naming the sibling it is not.

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?

Usage is only implied: the tool is for enumerating Db2 subsystems and the parenthetical 'requires DB2_LOCATION' signals a prerequisite. There is no statement of when to choose this over search_db2_catalog or list_environments, and no exclusion guidance.

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