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

Annotations already declare destructiveHint, idempotentHint, readOnlyHint=false, so the safety profile is covered. The description adds genuinely non-obvious merge semantics ('only the fields you send change; values merges into the existing values'), which is the key behavioral fact an agent needs. It does not say what a destructive change overwrites or how errors surface.

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?

Three short sentences, purpose first, then the non-obvious merge rule, then the caution. No filler and nothing buried.

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?

An output schema exists, so return values need not be explained, and the schema is rich enough to carry field-level requirements. Nothing critical is missing for a partial-update tool, though a note on what a destructive overwrite replaces would round it out.

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 six parameters in detail, giving a baseline of 3. The merge note for `values` adds marginal meaning beyond the schema's own field description, but no other parameter semantics are clarified.

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 ('Corrects an entry'), which separates it from create/log/archive/delete siblings. It does not explicitly name any alternative, so it falls short of the 5 bar for sibling differentiation.

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?

Implies usage (use this to correct an existing entry) and adds one real guideline: ask the person before changing something they did not mention. However, it gives no routing versus delete_entry or log_entry, and no precondition such as obtaining entryId from query_entries.

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