add_marker

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

No annotations are provided, so the description carries the full behavioral burden. It discloses that supplying end_bar yields a region, but that fact is already stated in the end_bar schema field, so the description adds little beyond it. Nothing is said about permissions, overlap with existing markers, reversibility, or failure modes for a mutation tool.

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?

A single tightly written sentence that front-loads the primary action and appends the conditional region behavior as a parenthetical example. Every clause earns its place with 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?

For a 5-parameter mutation tool with no annotations and no output schema, the description is thin: it omits ordering constraints (end_bar relative to bar), what happens to an existing marker of the same name, and confirmation of what is returned. The schema covers most parameter detail, but behavioral context is left largely unaddressed.

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 high (80%), with bar, beat, color, and end_bar each documented in the schema, so the baseline is 3. The description adds only the end_bar-as-region relationship and an illustrative example, which mildly reinforces but does not substantially extend the schema's own wording.

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 gives a specific verb ('Adds') and resource ('a marker'), plus a clear dual behavior: a marker, or a region when end_bar is supplied. It is distinct from siblings like edit_marker and delete_marker by virtue of the create verb, though it never explicitly names them to reinforce the distinction.

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 implicitly tells the agent when a region is created (when end_bar is given), which is useful conditional guidance, but offers no when-to-use-vs-alternatives framing, no prerequisites (e.g. project must be open), and no steering away from edit_marker for modifying existing markers.

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