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

Annotations only declare it is a non-destructive, idempotent, non-read-only mutation; the description adds that the default is shared across all conversations on the connection and can be moved by another conversation. It also warns that workspace refs are per-workspace ordinals whose meaning shifts after the switch, a consequence an agent could not infer from annotations.

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?

Front-loaded with the action and the definition of 'default', and every sentence carries real information. The ref-ordinal passage is dense but earns its place by explaining changed resolution semantics; still, the paragraph is long enough to test an agent's parsing.

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 one-parameter, annotation-covered, no-output-schema state mutation, the description covers the operation's scope, sharing behavior, and downstream reference-resolution effects. Nothing an agent needs to call it correctly is missing.

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 100%, so the baseline is 3, but the description adds meaning beyond the schema: the name is what lca_get(kind='workspaces') shows, backticks are optional, and the value's effect is the connection-wide default. The case-sensitivity nuance is already in the schema, so credit is partial.

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 workspace') and immediately defines what 'default' means, which is the crux of the tool. An agent can distinguish it from lca_create_workspace and lca_switch_engine without opening any schema.

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 clearly when the setting matters ('the workspace a call that names no workspace reads') and when it does not ('tools that save take `workspace` on every call and are unaffected'), which is real routing guidance. It stops short of naming sibling tools as alternatives, but the conditional framing is strong.

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