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

Annotations already declare destructiveHint=true, so the safety profile is known; the description still adds real value by disclosing that billed entries are deleted and the invoice record is lost as a consequence. It also scopes behavior ("never touches a running timer") and says what is returned. No mention of auth requirements or irreversibility beyond the invoice loss.

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: the action first, the scope boundary second, the risky consequence and alternative last. No filler, and the destructive caveat is placed where an agent will read it before invoking.

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?

For a single-parameter destructive tool with annotations covering safety and no output schema, the description supplies the consequence of deletion, the untouched case, the returned summary, and the correct alternative. Nothing essential to a correct call 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?

Only one parameter, already 100% documented in the schema as "Entry id from entry_list". The description repeats "by id" without adding format, provenance, or lookup guidance beyond the schema, so the baseline of 3 applies.

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 ("Delete one logged entry by id") plus the side effect of reporting the project and hours removed. It is immediately distinguishable from entry_edit and timer_stop, which the description also references.

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?

Explicitly routes corrections of billed entries to entry_edit instead, and clarifies the boundary against running timers. It stops short of a general "use this when" statement for non-billed entries, but the when-not and alternative are both named.

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