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

The description both declares a mutating action ('Reschedule an existing appointment', 'Sends updated SMS and email confirmations automatically') and asserts 'Strictly read-only, idempotent query with zero state mutation', directly contradicting its own content and the readOnlyHint=true annotation. It also gives no real context on whether the old slot is released, whether the new slot must first be verified, or what SMS/email side effects imply for the caller.

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?

The opening two sentences are useful and front-loaded, but the remainder is boilerplate that does not describe this tool: a tautological 'when to use', a 'Returns' block for a tool with no output schema, and generic 'canonical action URLs' language. Roughly half the text is template filler, and the filler is where the contradiction lives.

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 3-required-parameter booking mutation, an agent needs to know prerequisite availability checking, slot-release behavior, and authorization/ownership rules — none are covered. Worse, the behavioral block mislabels the operation as read-only, so the description actively leaves the agent less equipped than the schema alone would.

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% and the schema itself documents YYYY-MM-DD and HH:MM formats, so the description's flat list of required parameters adds nothing new. Baseline 3 applies; no extra semantics (timezone, booking-id provenance, date bounds) are contributed.

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?

The first sentence gives a specific verb+resource+effect: reschedule an existing appointment to a new date and time, with confirmations sent. It is distinguishable from siblings on the verb, though the tool name and title already carry most of that signal and the description never contrasts against cancel_booking/create_booking.

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?

The 'when to use' sentence merely restates the tool name ('Call this tool when you specifically need to execute reschedule_booking'), and the 'do not use' clause lists get_studio_info, get_scan_packages_and_pricing and get_gestational_guide — unrelated siblings — while ignoring the genuinely confusable ones (cancel_booking, create_booking, check_booking_availability). The routing guidance is templated noise rather than real discrimination.

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