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

Annotations already declare readOnlyHint=false, destructiveHint=true and idempotentHint=false, and the description is consistent with them while adding genuinely non-structured context: the link is a live credential for a real person, must never be posted elsewhere, and re-calling issues a fresh link. It stops short of explaining what 'destructive' actually destroys or any auth/permission requirements.

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 operation type, then the credential warning, then the repeat-call semantics, then the secret caveat. Four sentences, each carrying distinct information, with no boilerplate or restated schema.

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 15-parameter mutation tool with nested objects and no output schema, the description covers the mutation semantics, the returned join link, and the credential risk. It does not flag the region-picking pitfall or note that most parameters beyond `id` are optional, but the essentials for correct invocation are present.

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 93%, so the schema already documents nearly every parameter (id, user, server region, not_after, etc.) and the description adds no per-parameter meaning. The only non-schema detail, that the server's own `secret` is never returned, concerns output rather than inputs.

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 ('create a space, or reuse the one with the same id') plus the outcome ('get a join link (client_url) for one participant'). The 'WRITE:' prefix immediately separates it from the read-only siblings like lessonspace_list_spaces and lessonspace_get_session.

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?

Gives a clear context for use and the key reuse condition ('calling again with the same id reuses the space but issues a new link'), and warns it is 'not safe to repeat blindly'. It does not name an alternative tool or an explicit when-not-to-use case, but no sibling offers launch capability, so the gap is minor.

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