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

Beyond the annotations (readOnlyHint=false, idempotentHint=true, destructiveHint=false), the description discloses the full-replacement contract: every field must be passed, and omitting the note clears it. It also adds auth (owner-only) and plan-tier constraints that the annotations do not express. This is exactly the context an agent needs before a non-idempotent-looking overwrite.

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 replace semantics, then the read-first prerequisite, then permission and plan constraints. No filler.

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?

No output schema exists, and the description supplies what an agent needs for a 5-parameter mutation: replacement semantics, ownership restriction, plan gate, and a pointer to the read tools for current values.

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 baseline is 3, but the description adds meaning the schema does not: the operation is a wholesale replace, so all fields including note must be supplied, and a missing note is destructive of the existing value. The only gap is that it does not add format or coupling detail for id/taskId/date beyond the schema.

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?

"Rewrite one of the caller's own time entries" gives a specific verb (rewrite/update) plus resource (time entry), and narrows scope to the caller's own entries. It separates cleanly from log_time (create), delete_time_entry (remove), and get_task_time/list_time_entries (read).

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 states explicit prerequisites and alternatives: read current values with get_task_time or list_time_entries first, and only the entry's owner may change it. It also names an exclusion condition (Free workspace gets a plan-limit message), so the agent knows when the call will fail.

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