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

With destructiveHint=true, readOnlyHint=false and openWorldHint=false already declared, the description adds meaningful patch semantics ('only fields provided will be changed; all other fields remain as-is'), which is the key behavioral fact an updating agent needs. It still omits irreversibility, permission requirements, and what happens if a field is sent as empty.

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?

Four short sentences, front-loaded with the core action and patch semantics before the use cases. Everything is relevant, though the use-case list partially repeats the metrics guidance that the schema also supplies.

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 description covers action, partial-update behavior and target scenarios. A uuid error case or the fact that the entry must exist first would round it out, but nothing essential to invoking 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 100%, so every parameter is already fully documented in the schema, including the type enum mapping and the three-number metrics rule. The description's mentions of metrics, entry_date and description largely restate that, adding no syntax or edge-case detail beyond the schema baseline.

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 opens with a specific verb and resource ('Updates an existing career journal entry'), which cleanly separates it from add_career_entry, delete_career_entry and list_career_entries without needing careful reading. The follow-up sentence about only changing provided fields further scopes it as a partial update rather than a create or replace.

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?

It names concrete usage scenarios (refine descriptions, backfill metrics, correct the date, re-type an entry) and explicitly states it is the right tool for backfilling the three-number metrics breakdown. There are no explicit when-not-to-use statements, and it assumes the agent has already found the entry via a sibling tool rather than saying so.

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