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

Annotations already declare readOnlyHint=false, destructiveHint=true and openWorldHint=true, so the mutation/open-world profile is covered. The description adds genuinely new behavioral context beyond that: only passed fields are mutated, empty string means 'keep current', and content is ignored when content_blocks is set — all non-obvious mutation semantics that prevent accidental overwrites.

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 partial-update rule is front-loaded in the first paragraph, and the Args list is long but justified given 14 undocumented parameters. Every line earns its place; the only mild redundancy is the repeated '(leave empty to keep current)' pattern, which could have been stated once.

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 an output schema present, return values need not be described, and all 14 parameters plus the content/content_blocks interaction are covered. For a mutation tool with zero schema documentation and three annotations, nothing an agent needs to invoke it correctly is missing.

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 0% (all 14 params have titles only), so the description carries the full burden — and it does: every parameter is documented with meaning, format hints (post_id as UUID or full SK, comma-separated categories/tags with examples), keep-current semantics, and length constraints for SEO fields. This is model compensation for the coverage 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?

States a specific verb and resource ('Update an existing CMS blog post') and immediately defines the scope of that update as a partial patch, which is the key thing distinguishing it from create_cms_post/delete_cms_post. An agent knows exactly what operation this is 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?

Usage is implied by 'Update an existing' and the partial-patch semantics, and the content-vs-content_blocks precedence rule is useful invocation guidance. However, it never names an alternative or states when not to use it — e.g. it doesn't clarify the relationship to publish_cms_post or update_page, so routing guidance is left to inference.

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