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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the description's 'Read-only' line is redundant. What it does add beyond the annotations is meaningful: the link's purpose, and the hard limitation that this server cannot transmit media, which prevents a failed attempt at sending a photo or video. It does not cover link lifetime or what happens if the player has no WhatsApp connection, so it is not fully complete.

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?

Two tight sentences, front-loaded with what the tool returns before the usage condition. The trailing 'Read-only' restates readOnlyHint=true and could be dropped without losing information, but the rest of the wording earns its place.

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 no-parameter, read-only link getter with annotations covering the safety profile, the description supplies purpose, trigger and the key limitation, which is enough to call it correctly. Gaps are minor: it does not say whether the link expires or requires the player to have an existing connection.

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?

The tool takes zero parameters, so the baseline is 4 and there is no schema surface for the description to supplement. Nothing is missing on this dimension.

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 concrete verb and resource: returns the link that opens the player's WhatsApp chat with Morris. The scope is unambiguous, and the note that media never goes through this server separates it functionally from data tools like get_swing_analyses. It stops short of naming a sibling it supersedes or is often confused with, so it lacks the explicit contrast a 5 would need.

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 an explicit trigger ('when they want Morris to analyse a swing video or a photo') and an explicit exclusion ('those go through that chat, never through this server, and you cannot send them yourself'). The agent knows both when to call this and what not to attempt instead, so nothing is left to inference.

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