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

The annotations already declare destructiveHint=true, readOnlyHint=false and idempotentHint=true, so the mutation profile is covered. The description adds the auth requirement ('Admins only'), which is genuine context not present in the structured fields. It does not describe what the old rule text is replaced with or whether a prior version is recoverable.

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 clauses with the action front-loaded and the ID source and permission constraint following. No filler, no redundancy.

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 three-parameter, fully documented mutation with no output schema, the description covers purpose, ID provenance, and the admin gate, while annotations carry the destructive/idempotent profile. Only minor gaps remain around replace-vs-merge semantics and error behavior for invalid ids.

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 all three parameters are already documented, including the 'from get_training_overview' provenance for ruleId that the description merely repeats. It adds no syntax, format, or constraint detail beyond the schema, so 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 and resource ('Rewrite one playbook rule'), and the singular 'one' scopes it to a single existing rule, implicitly distinguishing it from the sibling add_playbook_rule. It stops short of explicitly naming the alternative, but an agent can tell add from rewrite.

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 description gives invocation prerequisites ('ids from get_training_overview') and a permission gate ('Admins only'), which help the agent decide if it can call the tool. However, it offers no explicit when-to-use vs when-not guidance or naming of the add/update sibling pair as alternatives.

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