add_message_log_entry

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

Goes well beyond the annotations: entries are in-memory for the editor session and never saved, an unrecognised severity silently degrades to Info, and a missing log_name or message is an error. These are non-obvious behaviors an agent must know and are not derivable from readOnlyHint/destructiveHint.

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?

Front-loaded with the verb and tightly packed, with zero filler. It is a single very long semicolon-chained sentence plus a Returns line, which is dense to parse, but every clause carries information an agent needs.

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, yet the description supplies the full return shape and explains message_count ('the listing's message count after the add'). Combined with lifetime, severity fallback, error behavior, and sibling routing, nothing needed to invoke 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 coverage is 100%, so the baseline is 3, but the description adds real meaning: the severity coercion rule and the error condition for the two required params. The log_name example values ('PIE', 'MapCheck') and the on-demand creation of new listings also clarify semantics beyond the schema text.

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 ('Add one message to a named editor Message Log listing') and immediately names the sibling it is not ('print_to_output_log writes to the Output Log instead'). An agent can distinguish this from the other log tools without opening any 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?

Gives explicit routing: 'Use it for diagnostics meant for Window > Message Log; print_to_output_log writes to the Output Log instead.' It also names the full companion set (get_message_log_entries to read back, open_message_log to show, clear_message_log to empty), so the agent knows the whole workflow, not just this call.

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