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

Goes beyond the annotations by disclosing a side effect an agent must know: connecting replaces any different Instagram account already on the project, and "every connection does" this. That is valuable mutation context not encoded in destructiveHint=false or idempotentHint=false, though the replacement behavior sits in mild tension with destructiveHint=false and the description never says what happens on auth failure or whether the previous account's data survives.

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?

Three short sentences, front-loaded with the action, then the optional-parameter shortcut, then the replacement warning. Every sentence carries distinct information and none repeats the schema or title.

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 connect tool with annotations covering the safety profile and no output schema, the description covers discovery, parameter omission, and the replacement side effect. Only failure/auth behavior and the exact return effect are unstated, which is a minor gap.

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 schema already documents instagramId at 100% coverage and shows it is optional, but the description adds the decision rule for omitting it (only one account available) that the schema cannot express. This is genuine semantic value beyond the structured field.

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 ("Connects an Instagram business account") and anchors it to the discovery sibling list_instagram_accounts, so an agent knows exactly which account object it operates on. It is distinguishable from generic connect_account and choose_facebook_page by naming the Instagram business-account resource explicitly.

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 concrete conditional rule: if only one account is available, instagramId can be omitted, which is real when-to-use guidance. It does not, however, say when to prefer this over the generic connect_account sibling, so routing between the two 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.