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

Annotations declare mutation (readOnlyHint=false), idempotency, and non-destructiveness; the description substantiates these with concrete behavior: nothing saved moves, no s/a/c/b/v refs are affected, and catalog refs stay bound to their minting database, with lca_compose_*/lca_edit_* refusing cross-database member refs. This is exactly the kind of beyond-annotation detail that earns a 5.

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?

Purpose is front-loaded in the first sentence, and the subsequent sentences on ref behavior all earn their place. It is dense and fairly long, but no sentence is filler, so it stays near the top of the range.

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 single-parameter mutation tool with no output schema, the description covers the non-obvious consequences (shared default, unaffected saved systems, ref binding, compose/edit refusals) thoroughly enough that an agent needs nothing more to call it correctly.

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 schema already documents case-insensitive matching, optional backticks, and verbatim copying. The description's 'as shown, matched case-insensitively' note largely restates the schema, so the baseline 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?

States a specific verb and resource: 'Set this connection's default engine database.' It further defines the scope of that default and implicitly distinguishes itself from the sibling lca_switch_workspace by operating on the engine rather than the workspace.

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?

Explains the context in which the default matters (browsing/composing calls that name no engine) and the downstream conditions that follow a switch, e.g. members for a new system must come from searches run afterward. It does not state explicit when-not-to-use or name an alternative switch tool directly, so it falls short of a 5.

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