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

Annotations declare destructiveHint=true and readOnlyHint=false, and the description reinforces this with "Overwrites the given fields; previous values are not kept." It also adds operational context about active prompts consuming plan quota, which goes beyond the annotations. It does not mention auth requirements or rate limits, so it earns a 4 rather than 5.

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 core purpose sentence sits behind a scheduling/quota preamble, so the definition is not front-loaded with the verb+resource. It also re-states schema parameter semantics, adding some redundancy; the content is reasonable but not tightly trimmed.

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?

With no output schema and a fully-covered input schema, the description covers what the tool does, its overwrite behavior, and the quota context for active prompts. It omits any indication of what the call returns, which is a minor gap for a mutation tool.

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%, so the schema already documents all five parameters including monitor_id adjustment and tag replacement. The description largely repeats those semantics ("move the prompt to another monitor in the same project", "replace the prompt's full set of tag ids") without adding syntax or format details, so baseline 3 is appropriate.

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 description uses a specific verb+resource ("Update an existing prompt") and clarifies mutation semantics, which separates it from create-prompt-tool and delete-prompt-tool. It stops short of naming siblings or explicitly contrasting, so it's clear but not maximally differentiated.

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?

It gives useful field-level guidance ("send only the fields to change", use monitor_id to move, tags to replace the full set), which implies when fields apply. However there is no explicit when-to-use vs alternatives, no prerequisites, and no when-not guidance, so usage is implied rather than spelled out.

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