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

Annotations declare destructiveHint=true, but the description goes further by specifying the exact consequence: the previous text is replaced and not kept, and that the change should be user-confirmed. That is genuine added context beyond the structured hints, though permission requirements and response behavior remain unstated.

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 compact sentences: the mutation and its IRREVERSIBLE overwrite semantics are front-loaded, with the confirmation caveat second. Every clause earns its place and nothing is padded.

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 4-parameter mutation with annotations present and no output schema, the definition covers what the tool does, which arguments change, that partial updates are allowed ('and/or'), the overwrite consequence, and where to get the replyId. Return-value behavior is not described, but with no output schema that 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?

Schema description coverage is 100%, including length limits and idempotency-key semantics, so the schema carries the parameter burden. The description only restates the replyId provenance and the 'and/or' partial-update shape, adding little beyond the schema — the baseline 3 applies.

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+resource ('Change the title and/or text of a saved reply') and names the source of the identifier, so it is clearly distinguishable from create_reply_template and delete_reply_template in the sibling list. An agent can tell what it does without opening the schema.

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 workflow hint by pointing at list_saved_replies for the replyId and instructs the agent to confirm with the user before committing. However, it never states when this tool is the right choice versus alternatives such as create_reply_template or the welcome-message editing tools, so usage is only implied.

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