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

Annotations already declare non-readOnly, openWorld, non-idempotent and non-destructive, so the safety profile is covered. The description adds the owner-only permission requirement, which is genuinely useful. It says nothing about what happens on success (notification, invite expiry) or failure modes, and the truncated sentence leaves behavior partially undisclosed.

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-loading 'Owner only' is good structure and the sentence is short, but it terminates mid-clause ('they...'), which wastes the space it does use and leaves the most informative part missing.

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 two-required-param mutation with zero schema descriptions and no output schema, the description should clarify argument meaning and the resulting effect. It covers the permission gate but not parameter meaning, success behavior, or error cases, and is truncated.

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 0% and both required params ('id', 'who') are bare strings. The description only obliquely implies 'who' is a contact identifier and 'id' is the private channel, without stating expected format, whether it's a channel id or name, or how to reference 'anyone open to contact'. Substantial gap remains.

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 (invite) and resource (private channel) and names the actor constraint 'Owner only'. The 'private' qualifier plus 'your private channel' distinguishes it from channel_invite/space_invite siblings, though the sentence is truncated so the full scope is never completed.

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?

'Owner only' and 'accepted contact (or anyone open to contact)' give a precondition and eligibility rule, which is real guidance. But there is no explicit when-not or named alternative (e.g. private_join vs channel_invite), and the trailing clause is cut off, so usage context is only implied.

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