Update the security policy (patch semantics; session only)

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

Annotations declare readOnlyHint=false and idempotentHint=true, so the write/idempotency profile is already covered; the description goes further by disclosing the confirm-gate behavior (nothing is sent and a request preview is returned without confirm: true) and explicitly warning that there is no server-side dry run. That is genuine added context an agent would otherwise have to discover by trial. It does not contradict any annotation.

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 with the operation and its critical safety gate front-loaded. The repeated parenthetical title text is slightly redundant, but nothing else is wasted and the most decision-relevant fact (confirm required to execute) arrives early.

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, the description helpfully explains what comes back when confirm is omitted, which covers the response shape adequately. However, for a mutation tool with a nested, entirely undocumented body of security-relevant settings, the definition says nothing about which fields can be patched or what omitting a field does under patch semantics.

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 67%, so the schema already documents confirm and idempotencyKey; the description restates the confirm behavior without adding syntax or format detail. The nested body object's fields (retention, sessionTtlHours, apiKeyMaxAgeDays, sessionIdleMinutes) carry no description in either place, and the description does not compensate for that gap.

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 states a specific verb and resource ('Update the security policy') and adds two scoping qualifiers, patch semantics and session-only, plus the endpoint path. It is clearly distinguishable from the read-side sibling security_getPolicy, though the first clause is largely a restatement of the title.

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?

Usage is only implied: 'patch semantics' signals partial updates and 'session only' signals scope, but there is no explicit when-to-use, no guidance on reading the current policy first via security_getPolicy, and no statement of what this tool should not be used for. The confirm gate is described, but that is execution mechanics rather than selection guidance.

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