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

Annotations declare destructiveHint=true, and "Edit" is consistent with that mutation profile. Beyond the annotation, the description only adds the PUT endpoint path; it does not disclose reversibility, required permissions, or side effects of reassigning task_id, so it adds limited behavioral context on top of what annotations already carry.

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, front-loaded with the verb and editable fields, then the conditional rule. The trailing "Paymo: PUT /api/entries/{id}" is mild restatement but compact and harmless.

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, so return values need not be described, and the schema fully documents the 7 parameters. For a mutation tool the description covers what can be edited and the entry-type branching, though it omits permission/reversibility context that the single destructiveHint annotation does not supply.

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 cross-parameter conditional logic absent from the flat schema descriptions: duration_seconds applies only to date+duration entries while start/end entries must change end_time instead. That link between parameters is genuinely useful 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?

States a specific verb+resource ("Edit a time entry") and enumerates the editable surfaces (description, task, length), which clearly separates it from paymo_create_time_entry and paymo_list_time_entries. An agent can identify the operation 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?

The description gives useful conditional routing between duration_seconds (date+duration entries) and end_time (start/end entries), which is real invocation guidance. However, it offers no explicit when-to-use vs alternatives (e.g., create vs update, or timer-based flows through paymo_start_timer/paymo_stop_timer), so usage selection is only implied.

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